求翻译：地下铁路（Underground Railroad）是19世纪在美国废奴主义者把黑奴送到自由州、加拿大、墨西哥，以至海外的秘密网络。虽然官方承认只有6,000人透过“地下铁路”脱离奴役，但另估计在1810至1850年之间，逃离的数字有大约30,000至100,000之多。它是自由的非裔美国人的历史的重要象征是什么意思？

Mass Transit Railway (Underground Railroad) is a 19th century abolitionist in the United States to free the slaves states, Canada, Mexico, and overseas secret network. Although only 6,000 people officially recognized by the "underground railway" from slavery, but the other estimated between 1810-185

Mass Transit Railway (MTR) (Underground Railroad) is a 19th-century abolitionist in the United States sent to the black slaves free State, Canada, Mexico, and overseas secret networks. Although the official recognition that only 6,000 people through the "underground railway" from slavery, but on the

The underground railway (Underground Railroad) is the 19th century delivers in the American waste slave principle the black slave free state, Canada, Mexico, down to overseas secret network.Although the official acknowledgment only then 6,000 people penetrate “the underground railway” to be separate

The MTR (Underground Railroad) is a 19th century United States abolition activists sent slaves to free States, Canada, and Mexico, and overseas secret networks. Although officially recognized only 6,000 people through the "underground railway" from servitude, but other estimates between 1810-1850 an

The MTR (Underground Railroad) is a 19th century United States abolition activists sent slaves to free States, Canada, and Mexico, and overseas secret networks. Although officially recognized only 6,000 people through the "underground railway" from servitude, but other estimates between 1810-1850 an