Wellesley is a town in Norfolk County, Massachusetts, United States. It is part of Greater Boston. It is best known as the home of Wellesley College and Babson College. The Hunnewell Arboretum abuts the Wellesley campus, and the Elm Bank Horticulture Center has its entrance in Wellesley, although it is located across a small private bridge over the Charles River and is therefore in the neighboring town of Dover. The town is noted for being among the most expensive zip codes in the United States, and likewise for possessing the second greatest concentration of residents with advanced degrees in the country. The public education services of the town are very well regarded, especially Wellesley High School; in 2007 it was ranked 70th best public high school in the nation by U.S. News & World Report, earning a Gold Medal. The town designated Cottage Street and its nearby alleys as the historic district in its zoning plan. Most houses in this district were built around the 1860s and qualify as protected buildings certified by the town's historic commission.