Red Granite

Historical marker location:

214 Monsignor O'Brien Hwy, Cambridge, Massachusetts

( Marker is on Charles River Dam Road (Massachusetts Route 28) 0.1 miles east of Edwin H Land Boulevard, on the right when traveling east.)

Aswan Quarries, Egypt. Over 600 million years old.

The first American subway system was built in Boston in 1897, running from downtown Boston to the neighboring city of Cambridge.