Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Pyramid:

"

Many square flat-topped mound tombs in China. The first emperor Qin Shi Huang (c. 221 BC, who unified the seven pre-imperial kingdoms) was buried under a large mound outside modern-day Xi'an. In the following centuries about a dozen more Han dynasty royal persons were also buried under flat-topped pyramidal earthworks.[citation needed]