China Circumnavigated The Globe In 1423?

Plans are afoot to try and emulate the travels of a Chinese eunuch who is believed to have discovered America more than 70 years before Christopher Columbus. Admiral Zheng He is extremely well known in China, where he is considered one of the pioneers of marine exploration. But he is virtually unknown in the West, where it is widely considered that Columbus discovered the "New World" first in 1492, although many Scandinavian historians claim the Vikings beat him by nearly 500 years. Gavin Menzies, a retired British submarine commander who is bringing out a book on Zhang He next month, says many academics not just in China but also on the West Coast of the US believe he found North America and Australia during a two-year odyssey which began in 1421.
http://news.bbc.co.uk/1/hi/sci/tech/2349929.stm