This remote sandstone cliff has one of the richest collections of Livonian petroglyph marks.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

This former KGB building is now a museum memorializing the people who suffered during the Soviet regime.

Outstanding, eerie frescoes and decorations fill this 19th-century monastery.

A clerical error gave rise to this imaginary micronation in the southwestern corner of Estonia.

This enigmatic artifact remained buried in a churchyard for years.

A lush oasis full of vibrant plants and striking geometric displays.

This 700-year-old structure is one of the most unique architectural and historic monuments in Gdańsk.

This old and disused water tower has received a new life as an art gallery with a piano staircase.

A forest park outside Tallinn full of architectural and artistic curiosities.

This obscene artwork on the side of a newspaper office pokes fun at a rival paper's former editor-in-chief.

A peculiar trapezoidal building covered with wonderful humorous reliefs.

Several of these strange cone-shaped bunkers can still be seen around the former Nazi headquarters.

A small and surprising passageway in Saint Petersburg devoted to the Beatles.

A wonderfully versatile natural history curio cabinet preserved since the 1840s.

This neighborhood of futuristic ball houses looks like an alien settlement in a science fiction film.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

A Neolithic celestial calendar standing in a nondescript wheat field.

This imposing 20th-century castle was abandoned before it was ever completed.

A World War II torpedo launch station abandoned off the Polish coast.

The two abandoned overpasses are among the largest bridges in Poland.

An abandoned 14th-century castle and prison complex on a small island in the Neva River.

This 15th-century cave complex is one of the very few monasteries to stay open throughout World War II and the Soviet regime.

Crooked windswept pines give this old forest an enchanted and magical look.