Lexington, Massachusetts

Lexington is a suburban town in Middlesex County, Massachusetts, United States, about 16 km from downtown Boston. First settled by Europeans around 1642 as part of Cambridge, it became a separate town in 1713. On 19 April 1775 the first battle of the American Revolutionary War was fought on its common, now called the Battle Green. The astronomer Cecilia Payne-Gaposchkin, whose 1925 doctoral thesis showed that stars are made mainly of hydrogen and helium, settled in Lexington with her husband Sergei Gaposchkin after their marriage in 1934.