The Charles River Esplanade in Boston is lined with benches accompanied by small plaques featuring inspirational words, quotes, and personal messages to friends and loved ones. Among them, there is one plaque with no words at all. Instead, it displays the first 120 digits of the mathematical constant, pi (π). Who sponsored the $5,000 plaque is unknown; many suspect it was MIT. It was one of our first stops for Jeanine, Kris, and me on a walking tour of Boston and Cambridge. We took in the Harvard Bridge, esplanade, Hatch Memorial Shell, Longfellow Bridge, Kendall Square, the MIT Stata Center, and Building 10. After the 3-1/2 mile walk, we jumped in the car and headed over to Harvard Square for more sightseeing and ice cream. An early dinner at the Dumpling House fortified us for a visit to the Auburn Cemetery and climb to the top of the Washington Tower.