Brisbane's manmade urban beach has enough water to fill five Olympic-sized swimming pools.

A double cantilever system bridge that was designed to prevent flood damage.

The longest staircase lock in Britain.

Largest lake in Great Britain measured by surface area.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

Follow the original medieval paths that wind through this intriguing section of the city.

Semaphore saints, a golden dragon's head, and a stone carved with religious warnings all call this cathedral home.

The prototype for all Nazi concentration camps.

This riverside restaurant has been serving customers since 1146.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

The remains of a convent turned military barrack in the heart of Madrid.

An ancient Egyptian temple in the middle of Madrid, Spain.

The modern birthplace of Irish freedom.

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

The world's largest collection of ship figureheads includes figures from legends and history alike, from Sir Lancelot to Abraham Lincoln.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

The commemorative stone column conceals a secret laboratory.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

This legendary stone is of unknown origin, and throughout history has been a literal touchstone for British leaders.