There are certain cities that tourists have visited in droves for centuries. Places like London and Paris seem to have a popularity that cannot be eroded by the passage of time. For other major cities, however, their tourism ebbs and flows with different political climates and cultural revolutions.

So how do we determine which major urban centers will be popular in 2018? We ask travel agents. Even in the internet age, travel agents are some of the few people who understand how tourists choose where they take their vacations.

This list will countdown 2018's most popular urban destinations, according to travel agents. In compiling my research for this article, I looked at several popular travel sites and also interviewed some of my friends who are travel agents. Many of the entries on this list are in highly developed nations like the United States and Great Britain but a surprising number were also from the developing world. It will be interesting to see if this trend towards exotic, unique vacations will continue. If you have any urban destinations that you are planning in 2018 that did not make this list, feel free to mention them in the comments.

20 Paris - Charm that goes on forever

I don’t know if Paris will ever lose its charm as a tourist destination. As far as major cities go it certainly wasn’t the best place that I’ve ever visited, but the place has such a mystique that unwary travelers will throng there every year.

Paris is known as the city of romance and countless movies and TV shows have reinforced this image over the years. Because of this, Paris is an extremely popular destination for couples, especially ones on their honeymoon.

Paris is also known as an important international hub for art and architecture. The city has a lot to offer that makes it popular among tourists.

19 Rio de Janeiro - South America's Tourist Hotspot

When people think of major urban centers, Rio de Janeiro, Brazil probably isn’t the first place that they think of. This is a misconception, however, as Rio is easily the most prominent city in South America.

Just because this city isn’t a giant, concrete monolith like New York City or Chicago, doesn’t mean that it isn’t urban. In fact, it is exactly these features that makes Rio such a popular tourist destination. Everyone has seen the iconic images of the giant Jesus statue overlooking Rio Harbor, and the rest of the city is just as beautiful.

In addition, Rio provides tourists with a change of pace from the old world

18 Toronto - the most visited city in Canada

I absolutely love Toronto. It has everything that places like New York City and Chicago have to offer without feeling overcrowded and oppressive like other major cities.

Therefore, I was very glad to find that Toronto is one of the most popular cities in the world among tourists in 2018. I only spent a week there in 2015 but I would be totally willing to go back. There were tons of things to do and traveling and staying in the city were very affordable. It isn’t surprising to me that Toronto is the most visited city in Canada.

17 Boston - the heart of the US revolution

There isn't another city on this list that I have spent as much time in as I have in Boston. After living in Boston for over a year, I can attest that it is very tourist friendly. There are a ton of hotels and attractions, the public transportation is (somewhat) navigable, and businesses in general seem very amenable to people visiting the city.

Boston was the heart of the US revolution, so it is understandable why so many people from the United States vacation here, but Boston is also hugely popular among international tourists. Boston is also close to other major cities like Providence and New York City.

16 Moscow - Rich in history but not exactly designed for tourists

I have talked in other articles about how more and more people from the US (particularly youth) are traveling to Russia for vacations. This was validated by my research for this article because travel agents are increasingly being asked about Moscow, Russia's capital.

I think it would be kind of cool to go to Russia but I have to admit that Moscow is an odd choice for a standard tourist. The city is not built around tourism, so there are not the kind of amenities that one would expect when visiting a major city. But it is hard to pass up the chance to experience a place that is so rich in history.

Our next entry is an urban destination that is incredibly popular in any year. New York City is unquestionably one of, if not the grandest city in the world. It has its share of problems, and you can argue that there are cities that are better to live in and visit, but there is nowhere else on earth that can rival the size and diversity of the big apple.

I think that one of the coolest things about New York City is that people come from all over the United States and the rest of the world to visit it. It is truly a global city and somewhere that everyone should visit at least once in their life.

14 Nassau - Spiking interest in the authentic Bahamas experience

We already know that the Bahamas' islands are one of the most popular vacation spots in the world. In recent years, however, more and more people are specifically visiting Nassau, the country's capital. In the past, resorts like Atlantis Paradise Island saw the majority of tourists but it seems like this year's visitors are interested in the authentic Bahamas experience.

Even if you decide to stay in the city, it is only a short bus or taxi ride to the beach. Nassau has also taken serious steps recently to ensure the safety of people in its city, so that may be partially responsible for this rise in tourism.

13 Chicago - One of the USA's premier (summer) destinations

The creation of a city like Chicago hundreds of miles inland in the 19th century was a bit of an anomaly. Cities like Boston and Philadelphia were founded along the coast because it made it so settlers could easily access ships incoming from Europe.

From its unconventional beginnings, Chicago has become one of the United States' premier tourist destinations. The city is off the coast of Lake Michigan (one of the Great Lakes) so tourists have other things to visit besides your typical city attractions. It is also worth noting that most of Chicago’s tourism happens in the summer, when the city isn’t freezing cold.

12 Washington D.C. - Tourists flock to the capitol

This entry is obviously wrapped in US exceptionalism, but there is something to be said for Washington D.C. as a tourist destination.

D.C. is not only the capital of the United States, it is also the place where we house the majority of our national artifacts. The White House, the Lincoln and Washington Monuments, and Arlington National Cemetery are all found here. This doesn't even include the dozens of museums and monuments administered by the Smithsonian.

Hundreds of thousands of tourists come to D.C. every year, most from the United States but also many from foreign countries.

11 London - Countless things to do and see

Some people within the British government were worried that a potential Brexit would be disastrous for Britain's tourism industry. If this list is any indication, those fears were unfounded.

Just like every other year since the end of WWII, London is one of 2018's most attractive tourist destinations. There is simply so much to see and do in London. Big Ben, the Royal Palace, and the London Eye are just a few of the cities attractions. It is also worth mentioning that London is easy to travel to from Europe and the east coast of the United States.

10 Cape Town - An improving international reputation

I was very surprised to see an a city in Africa on this list. Despite being one of the largest continents, the reputation of many countries in Africa as hubs for sketchy behavior tends to scare away prospective tourists. In addition, because many of its economies are still developing, they do not have the infrastructure set up to house a huge influx of tourists.

It is very promising for South Africa (and Africa in general) that Cape Town makes this list. The country has come a long way since its noted history. As they become more developed and their international reputation continues to improve, they will see more tourists. It's a beautiful city.

9 Hong Kong - incredibly unique history

The city of Hong Kong has an interesting history. It first became distinct from mainland China because it was administered by the British as part of their colonial empire. Hong Kong enabled the British to efficiently trade their wares for tea, which they then traded to the rest of the world.

Hong Kong is no longer controlled by the British (at least not officially) but it still is independent from China. This incredibly unique history has made Hong Kong a very sought-after destination, a fact that is reflected on this list. I myself went to Hong Kong a couple of summers ago and had a very good time.

8 Los Angeles - The mecca of cinema

There is no other city in the world like Los Angeles and this attracts millions of tourists to southern California every year. Hollywood is consistently the main attraction in LA as people continue to be fascinated with the ways and places that movies are filmed.

Many people also travel to LA (or just outside the city) to visit their beautiful beaches. I have been to several beaches on both coasts of the United States and I have to admit that LA has some of the nicest. Tourism to LA has stayed pretty constant over the years and there is no expectation that this is going to change in 2018 or beyond.

7 Istanbul - Jump from Europe to Asia

I was very surprised to find Istanbul on this list. I know that this large city has a lot to offer, but it is not the first place that I think of when I think about major tourist destinations. Istanbul, once called Constantinople, was the early seat of the Eastern Roman Empire. The city has changed hands several times since then, which partly explains why the city is so ethnically and culturally diverse.

Walking through the streets, you will notice a significant difference in the architecture of different parts of the city. This signals that those neighborhoods were built during different eras when different powers were in charge of the city.

6 Dublin - Welcome to the mythical Ireland

It would be impossible for any city in Ireland to live up to the reputation given to the island from the movies and television shows, but the capital city of Dublin does its very best. This is the only true “city” in Ireland and, therefore, this is where everyone goes to have a good time.

Thus, Dublin has earned its reputation as the city to go to if you want to experience Irish culture and have a really good time. Hundreds of thousands of tourists flock to Dublin every year to chase the mythical Ireland that they know from pop culture. They may not find it in this city but they certainly don’t leave disappointed.

5 Barcelona - Art, music and culture

Barcelona’s tourism industry will take a serious hit if high schools ever stop sending high school seniors to Europe for a couple weeks. All of these high schools follow the same basic itinerary, with the main stops being London, Paris and Barcelona. Barcelona is the least visited of these three cities but that shouldn’t minimize the staggering number of tourists that this city receives every year.

Barcelona is most attractive as an exhibit on the country's music and culture. The cities art scene is always vibrant and there are several famous musicians who got their start in Barcelona.

4 Athens - like three vacations in one

I was not surprised to see that Athens is one of the most popular urban destinations in 2018. I am planning my own trip to Greece’s capital, although I will be going in 2019. To me, Athens has everything you can hope for in a vacation destination. It has tons of attractions and things to do, it offers a booming city life, and there are nearby beaches (accompanied by the moderate climate) where you can go to escape the hustle and bustle of city life. It is really like having three vacations in one.

The major cities around the Mediterranean Sea are well represented in this article.

3 Tokyo - Nothing else quite like it

I read an article recently that argued that every Western Europe city provides the same basic experience. I think that this is a little unfair, but there is something to be said for finding an urban destination that provides a totally different experience from the one offered in places like London and Paris.

Tokyo provides this unique experience. Despite the fact that Japan became somewhat westernized after WWII, the capital city of Tokyo is still steeped in eastern culture. Things like fish foot massages, unique vending machines, and countless other aspects of Japanese culture are totally foreign to us.

Experiencing new things is exactly what visiting a new country is all about.

2 Montreal (Quebec) - Undeservingly in Toronto's Shadow

I think that Canada can fairly be split into two segments. There is the English-speaking portion, personified by the city of Toronto and there is the French-speaking section, typified by the province and city of Quebec.

Because the province of Quebec is so distinct from the rest of the country, it is an important place to visit for anyone hoping to understand Canadian culture. Montreal is the largest city in the province and is also one of the most popular tourist destinations in 2018. This wonderful city never quite gets the tourism that Toronto does, but it certainly gets enough to warrant the plethora of hotels and attractions that it has to offer.

1 Beijing - traditional eastern culture

Tourists have become increasingly interested in experiencing the culture of China. For a long time, making a trip to China meant going to Hong Kong. Hong Kong is still hugely popular (and is featured elsewhere on this list) but due to certain historical factors, it is heavily westernized.

The capital city of Beijing is more steeped in the traditional eastern culture. For centuries, the civilizations in China rivaled those of the west and the city has become increasingly conscious of its cultural history. Beijing also has a lot of hustle and bustle that tourists are attracted to. These factors might explain why Beijing has been one of the most requested travel destinations in 2018.