This recreated Roman outpost stands above its buried predecessor.

This gigantic monument hidden in the woods was built to thank the Dutch for sheltering Belgian refugees during World War I.

The fifth-longest natural arch in the world, and the longest outside China.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This natural hill rose another 130 feet from the debris and rubble added after World War II.

A mammoth WWII anti-air defense tower has been repurposed as a hotel with a rooftop garden.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

Amsterdam's former hotspot for public executions and dissections.

A first-of-its-kind circular bridge for cyclists.

A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.

The tiny, studious rodents greet visitors to the National Archives of Finland.

A historic structure inspired by Roman, Muslim, and Jewish bath houses.

A striking geological formation in Southern California.

This restaurant combines two Finnish traditions in one place: warm-weather relaxation and outdoor carpet-cleaning.

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

Dedicated to the outnumbered Finnish forces who pushed back Soviet forces during the conflict.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

This church also serves as a lighthouse complete with a beacon.

An abstract monument to a symphonic composer.

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

An alien church provides much needed silence in the midst of a Finland shopping center.