As a handsome hairdresser and a motorcyclist, Wang is very popular among girls in his hometown in Anxian County, Sichuan Province. After working in large cities for several years, the 35-year-old man finally settled down in his hometown to pursue his dream of building an airplane.

"I've been dreaming of flying my own plane since I was a kid," says Wang. His dream did not take long to achieve; he built his plane in just three months. From his first trial flight in 2005, his plane keeps reaching greater heights every time he pilots it. However, no one has been brave enough yet to accompany him.

Sichuan peasant Wang Qiang succeeds in flying his self-made plane.

"I hope that someday my girlfriend can sit beside me in the plane and fly with me," says Wang.

This romantic idea also occurred to Tan Chengnian, a peasant from Shandong Province, who tried to make a plane as a birthday gift for his wife. Unfortunately, he died when the plane crashed during its trial flight. The remains of the plane are also featured in Cai's exhibition.

"This is a monument to peasant inventors," says Cai. "He [Tan] paid the greatest price for his invention."

A family of robots

Cai's exhibition devotes an entire floor to the more than 20 robots created by Wu Yulu, a farmer from the suburbs of Beijing. Wu started his robot-making career when he was a first grade student in primary school. When other kids were on the playground, Wu liked to observe his classmates walking, running and jumping; his observations led him to build a robot that could move the same way humans do.