1321572 is a 9.7 mile (15.6 km) section of the Boston Marathon in Massachusetts, United States. This section of the marathon is considered to be the toughest and most iconic section, passing through the heart of Boston, from the Wellesley/Newton area to Kenmore Square at the finish line in Boston. This portion includes such well-known runners of Boston landmarks as the Boston College campus, Heartbreak Hill, the Brookline Hills and the Newton hills.