This colonial town in Colombia sits around the largest stone paved square in South America.

In the heart of Medellín, an artsy urban complex sets the stage for demonstrations and protests.

Aruba’s first chapel.

Bizarrely-painted church designed by a controversial artist.

Sturdy scales are a surprising thing to find in a modern European city.

In the middle of a Vienna square, Roman ruins dating back some 2,000 years are on display.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

This historic timepiece was a popular meeting place for romantic rendezvous in the 1960s.

The beautiful baroque library of the Hapsburg empire.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Op-art architecture designed for happiness.

Baroque celebration of the end of the Great Plague of Vienna.

A silly medieval mural preserved on the side of a Viennese house.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Apartment complexes built into huge repurposed natural gas tanks.

The solemn exterior conceals an opulent interior of this 17th century church.

An exquisite Baroque church in Vienna's old town.

An ornate private entrance to the Vienna subway built specifically for the emperor.

Along the edge of this fountain are 365 smaller fountains that represent the days of the year.

Double spiral staircases are not unheard of, but they are very rare.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

This medieval footbridge in the Swiss Alps is known to attract cliff-jumping daredevils.