Ancient Technology

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

Deep in a Polish forest, this collection of Iron Age megaliths still holds onto many of its ancient secrets.

No one knows why ancient labyrinths were built on this tiny northern island.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Hundreds of drawings left by the land's previous inhabitants remain mysterious.

Stonehenge has nothing on Castlerigg’s views.

The entire known universe of the ancient Etruscans is held inside this bronze model of a sheep’s liver.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

Huge stone depressions which may have acted as an Incan agricultural experiment.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

Astronomical observatory above Lake Titicaca.