Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The world's first electric battery-powered submarine.

An impressive display of ships and artifacts from the ancient Mediterranean maritime trade.

An ancient Roman theatre restored to its former glory in the Spanish city of Cartegena.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

This enormous censer uses a pulley system installed over 400 years ago.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.