Do you know your skylines?

With more than 35 million people, Tokyo is the world's most populous metropolis and is described as one of the three command centers for world economy. The tallest structure in Tokyo's cityscape is Tokyo Skytree, a lattice tower built in 2012. It's also Japan's tallest building.

Did you know that Chicago's skyline has three of America's five tallest buildings? If you count the antenna, Sears Tower is the country's second tallest skyscaper, after One World Trade Center in New York. The Trump Tower in Chicago is the newest member of the skyline, and comes in at No. 3 in the country.

Big Ben stands out in this shot of London's historic skyline. Though most everyone refers to the majestic tower as Big Ben, its real name is the Elizabeth Tower, named in tribute to Queen Elizabeth II. The nickname, locals say, is only referring to the bell of the clock, not the entire structure.

A view of the Tel Aviv skyline at sunset shows why this Israeli city is dubbed "The White City." Tel Aviv is known for its distinctive Bauhaus architecture, marked by assymetry, bold shapes and minimalistic light colors.

Located on a tiny peninsula west of Hong Kong overlooking the Pearl River, Macau is often nicknamed "the Las Vegas of Asia" due to its glitzy high-rise casinos and elaborate shopping malls.

Cologne's Gothic Cathedral, located along the Rhine River, is a UNESCO World Heritage Site that dominates this old-world European skyline. Cologne is the fourth-largest city in Germany with a history going back almost 2,000 years.

When we say "Seattle," you might think "Starbucks," "rain" and "Seahawks." But there's much more to this bustling city, like the legendary Space Needle that dominates this picturesque skyline.

It's Melbourne, mates! This vibrant city is the second most populous in Australia and was named the world's most livable city in 2014, according to the Economist Intelligence Unit.

As Argentina's capital, Buenos Aires is known for its European atmosphere, passionate tango culture and vibrant nightlife. Its stately buildings include Casa Rosada, the presidential palace; the Metropolitan Cathedral; and the Palace of the Argentine National Congress.

This city east of Tel Aviv may be small, but Ramat Gan is still home to Israel's tallest building, the Moshe Aviv Tower. Its high-tech economic base is one reason Israel is known worldwide as the startup nation.