Did the Chinese discover America ?

Who discover America, the Chinese or Christopher Columbus ? According to a copy of a 600-year-old map found in a second-hand book shop, the Chinese discovered America not Columbus. This document is purportedly an 18th century copy of a 1418 map charted by Chinese Admiral Zheng He which appears to show the New World in some detail. This document evidences that a Chinese sailor mapped the Western Hemisphere more than seven decades before Columbus. This information can be found in the book ¨Who Discover America¨ by Gavin Menzies. This book states that the traditional story of Columbus discovering the New World is absolute false, that it is a fantasy. Among Menzies other claims are that the first inhabitants of the Western Hemisphere didn´t come over land from the Bering Strait, but instead were Chinese sailors who first crossed the Pacific Ocean 40,000 years ago. The author of that book believes that Columbus had a map of the world that was plotted by the Chinese Admiral Zhen, who created the map when he sailed to the New World in 1421, more than seven decades before Columbus. He also claims that Zheng not only reached the New World, he left colonies there. His fleet also sailed around the tip of South America through the Strait of Megellan around the Gulf of Mexico and up the Mississippi. Observation: Some of these informations were taken from the internet. By Socrates Javier