Quiz time: What is the world's oldest massive reinforced-concrete structure? According to a November 19 article in the Boston Business Journal, it's Harvard Stadium in Allston, MA, just outside Boston. The 109-year-old stadium used nearly 9,260 cubic yards of concrete and is one of only three athletic arenas in the country to be designated a National Historic Landmark – the other two being the Yale Bowl, built in 1914, and the Rose Bowl, built in 1922. But you knew that.