Created as a "model concentration camp" to hide Nazi atrocities from the international community, this former camp-ghetto now holds a museum and memorial honoring the lives lost within.

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

This striking memorial is one of Estonia’s most controversial Soviet leftovers.

A large boulder was declared a local landmark by a popular vlogger.

Visitors can sit and study the board with this Estonian chess legend and International Grandmaster.

A statue of the Soviet leader still stands in a quiet corner of Estonia’s most Russian city.

A historic scientific breakthrough that crosses nine borders.

Tall columns of volcanic basalt make up this improbable-seeming rock formation.

A series of concentric circles represented a bold new experiment in socialist urban planning, and it notoriously difficult to get around.

This little gem in the Gulf of Riga has a very rich heritage and distinct culture.

Legend says lovers who hold hands while venturing along this stone jetty and kiss at the end will remain together forever.

After funding was cut for a memorial to the Danish author, the sculptor had his statue ceremonially lowered into the city harbor.

A small man-controlled waterfall powers an Art Nouveau elevator and is accessed via narrow gauge, solar-powered tramway.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

This behemoth bovine guards an Estonian town and is a memorial to the lost species.

First point in the Struve Geodetic Arc, a 19th century undertaking to measure the Earth's size and shape.

A spectacular Petrine Baroque summer palace commissioned for Catherine I by Peter the Great.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A former imperial sea-fortress and Soviet prison.

This historic little railroad runs through some of the most beautiful scenery in Germany.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

A lush indoor jungle fills this bustling Madrid transportation hub.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

A collection of items from a way of life that no longer exists.