Terracotta Army Pit 1 - in Xi'an, China. Image Source: Maros M r a z (Maros), Wikimedia Commons.
The terracotta army was discovered by accident in 1974 at Xian, in China, when local farmers digging a well broke into a pit containing 6000 life-size terracotta figures.
In a chance discovery, an entire army of terracotta warriors is found. The first emperor of China had them created and buried with him, to protect him in the afterlife.