An abandoned textile factory on the "island of crows" was home to Estonia's first workers' strike.

Historic slum of Tartu.

This stoic bronze soldier stands as a symbol of Russian sacrifice or Soviet oppression, or maybe both.

A historic scientific breakthrough that crosses nine borders.

The Guardian of Tallinn.

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

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

This old Estonian mine has been kept like a sprawling time capsule of the local shale industry.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

Once standing on solid ground, this slender beacon is a victim of the very shoreline it was charged with announcing.

Man-made mineral caves house massive bat colony.

A decommissioned submarine base makes a great space for graffiti art.

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

Mysterious craters may have been home to an ancient cult.

An eerie, derelict amusement park in Berlin.

A floating cat sanctuary on an Amsterdam canal.

A striking public sculpture representing the period of martial law in Communist Poland.

The 20-mile causeway that separates the Netherlands from the sea.

This historical Netherlands fortress still bears the marks of its single siege.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

Copenhagen's celebrated theme park and gardens.

Twisted buildings adorn the banks of the Rhine river.