Democrats regained control of the Senate and held the House after the 1986 elections. Texan Jim Wright succeeded the retiring Thomas P. “Tip” O’Neill of Massachusetts as Speaker. The 100th Congress (1987–1989) reacted to several crises. The biggest stock market crash in U.S. history brought the Reagan administration and Congress together in a “budget summit.” Select committees investigated the arms-for-hostage arrangement now known as Iran-Contra. Congress also overrode President Reagan’s veto of the Clean Water Act of 1987. The House and Senate also traveled to Philadelphia’s Congress Hall to commemorate the bicentennial of the U.S. Constitution.