Cambridge, located just across the Charles River from Boston, is a center for academia, biotechnology, politics, and tourism. This is also home to both MIT and Harvard University. To start your exploration of Cambridge, head to Harvard Square, a busy hub of activity with a mash-up of trendy stores, outdoor cafés, and colorful residents. Pick up a walking tour map at the Square's visitors information booth. The walk will take you through numerous historic sites, including Mount Auburn Cemetery, Tory Row, and the Longfellow National Historic Site.