Seen from distance, these structures look like huge mushrooms sprouting from beneath the earth, or “spacecraft” manned by human being-like creatures inhabiting a celestial body in the universe, which is far, far away from our globe. A bird’s-eye-view shows them standing side by side, forming something that resembles the Olympic rings. Stepping inside, you’ll have a feeling of being inside the Theater of Marcellus started by Caesar and completed by Augustus around the year 11 or 13 AD.

These structures, dubbed as "mysterious castles in the East" for their unique architectural style, are found at Yongding and other counties in Fujian Province, east China. Known as yuan tu lou "round, castle-like earthen buildings," they are home to the Hakka, a branch of the Han Chinese, the country’s majority ethnic group.

"Hakka" means "guest people," whose ancestors migrated from their homes in central China to border areas of what are now Fujian, Guangdong and Jiangxi provinces to flee war or famine. Numerous mass migrations are documented in classic Chinese history, the earliest taking place about 2,000 years ago and the latest, about 300 years ago. After settling in their new homelands, these immigrants came to be known as "Hakka" or "guest people." Their descendants  today still favor the address, even though it is a long time since their ancestors ceased to be "guests."

One tu lou structure at a village called Tianluokeng is recognized as most beautiful. A square-shaped building stands inside the complex, which is linked with four round buildings.

How to Build a Tu Lou Structure

A tu lou structure features walls built with rammed clay and sandy soil mixed up according to a certain ratio. In some cases, rammed earth bricks are also used. Structural parts - gates, doors, pillars, windows, etc. - are exclusively wooden.