Boston's Big Dig was a 1.5 mile (2.4 km) tunnel under the harbor, that cost 22 billion dollars and took 15 years to build. The BQE is 11.6 miles (18.7 km) long

Boston's Big Dig was a 1.5 mile (2.4 km) tunnel under the harbor, that cost 22 billion dollars and took 15 years to build. The BQE is 11.6 miles (18.7 km) long, and runs through Brooklyn and Queens.