Latvia's symbolic mountain-shaped national library is home to millions of cultural tomes.

The oldest housing complex in Riga is a mini timeline of architectural trends.

A famous burial ground with a history both grim and literary.

A unique tribute to the millions of animals who served and died for the British military.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

Repository for more than 22 million pickled specimens.

Eighty million natural history specimens call this gargantuan museum home.

A clock designed to run with perfect accuracy for 10,000 years.

This innovative steam machine was no doubt the most famous of the pioneer locomotives.

Charles Babbage's proto-computer, painstakingly brought to life.

Hidden beneath the streets of London is a secret subway that only carried mail.

Rat sculptures try to infiltrate the Graybar Building in an architectural tribute to New York City's nautical history.

These unassuming lighthouses have seen the first reading of the Pledge of Allegiance, the first wireless transmission, and more than one mystery.

One of the world's largest model railroads is a mind-boggling achievement.

A terrific purveyor of natural history objects and curios.

The only home that Alexander Hamilton ever owned has a history almost as troubled as his own.

The very first subway station in New York City is beautiful, decked out in chandeliers, and ... abandoned?

The oldest playground in America.

Historic Hull Street was actually the first street with a proper name in the Boston area.

Plymouth's huge yet little-known memorial to the Pilgrims.

The highest point in Texas is capped by a big silver pyramid.

Pennsylvania's highest point is spotted with boulders which were pushed to the surface by nothing but cold.

100 massive sculptures in the Hudson River Valley.

Site of a classic 19th-century physics experiment to prove the earth is rotating.