Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

Started as a kitchen garden, now the second largest botanical garden in the world.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

What was once thought to be a wellspring of unicorn bones is actually just a prehistoric burial site.

This historic stone bridge has an entire neighborhood clinging to its sides.

The fairy tale castle of the "fairy-tale king."

This modern museum of Mediterranean culture is surrounded by a surreal concrete honeycomb.

A beautiful maze marks where three countries meet.

Explore the complex ecology of this multifaceted nature preserve by riverboat.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

A mythically themed self-built sculpture park.

These warring psychedelic crags commemorate an unsuccessful military operation.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

This New Orleans statue of a portly figure in a goofy hat pays homage to a classic of satirical literature.

This angular Dwarven tunnel cuts through a mountainside in Glacier National Park.

An unfinished tomb carved into a giant boulder in the Arabian Desert.

A miniature city, once ruled by the Queen of the Netherlands.

This "social palace" housing complex created a relatively stable and self-contained worker's society... for a time.

These mammoth-yet-narrow crevasses in the Earth are perfect for taking an otherworldly swim.

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

A gorgeous medieval library where the books are kept in chains.

This 16th-century monastery has been turned into a surrealist architecture compound.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.