Benjamin Banneker, Oella, Md.
An accomplished astronomer, inventor, and mathematician in the late 18th century, Banneker is known as the First African-American Man of Science. He built the first American working clock made entirely of wood and penned several popular almanacs that contained eclipse calculations and other astronomical observations. The Benjamin Banneker Historical Park and Museum is located on the farm where he lived from age 5 on. It holds artifacts—pieces of pottery, clay pipes, slate pencils—from an archaeological excavation of the site. 300 Oella Ave., 410/887-1081, $3.