These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A tiny church on a man-made island in the Adriatic.

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.

A replica of the home of a famous fictional troll family.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

A small island dotted with old, historic Finnish buildings.

A subterranean house of worship carved right out of the bedrock.

During the Soviet era, the spire of this longstanding church was used as a radio transmission tower.

The Guardian of Tallinn.

Walk along the medieval fortifications that have been protecting Tallinn since the 14th century.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A little sculpture with a large wardrobe.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

This impressive coastal fortress was destroyed before it was finished.

This archipelago homestead-turned-museum has remained the same since its last resident, born in 1897, died in 1973.

The former home of Norway's greatest romantic composer.

This functioning parish church is also the site of many concert performances due to its wonderful acoustics.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

This L.A. fixture has been serving hot dogs out of a giant hot dog since 1946.

The Ortega family started their iconic food company in this small, adobe kitchen.

The abandoned personal amusement park of the King of Pop.