Complex sentence: The United States Capitol crypt is the large circular room filled with forty neoclassical Doric columns directly beneath the United States Capitol rotunda and was built originally to support the rotunda, as well offer an entrance to Washington's Tomb.
Split into simpler sentences: The United States Capitol crypt is the large circular room filled with forty neoclassical Doric columns directly beneath the United States Capitol rotunda. It was built originally to support the rotunda as well as offer an entrance to Washington's Tomb.