The dome-shaped reservoir of this old water tower produces unique acoustic effects.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Chewing gum tycoon's memorial lies perched over wife's botanical gardens on Santa Catalina Island.

A miniature world of concrete and stone in Springfield, Ohio.

The Egyptian-inspired last resting place of Lord Kilmorey.

Monasteries on rock pillars, once accessible only by frayed ropes.

Oakland's beautiful monumental cemetery.

The world's largest collection of ships in bottles.

The struggle of a small Dutch island against the sea.

A large camera obscura, constructed entirely from digitally fabricated components.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The final resting place of the poets Shelley and Keats.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

A miniature train-ride through Slovenia's largest cave system.

The bizarre rocks of Đavolja Varoš are the result of natural erosion.

A classically inspired temple in Redwood City.

The world's oldest model village.

Treehouse motel and treehouse-building school.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

One man's swirling six-acre monument of stone.

The world's largest fully steerable radio telescope.

One car at a time please.