The United States Congress
The United States Congress is part of the legislative branch and is made up of two houses -- the House of Representatives and the Senate. This two house system is known as a bicameral legislature. The primary duty of Congress is to write, debate, and pass bills, which are then passed on to the president for approval. Other congressional duties include investigating pressing national issues and supervising the executive and judicial branches.
Every two years, voters get to choose all 435 representatives and a third of the senators. The entire House membership faces re-election every two years, but the Senate is a continuing body because there is never an entirely new Senate. A new Congress begins in January following Congressional elections. Since the First Congress, which met from 1789 to 1791, all Congresses have been numbered in order. We are currently in the 110th Congress. Congress meets once every year and usually lasts from January 3rd to July 31st, but in special cases, a session can last longer.
For the most part, the House and Senate each meet in their respective chamber in the U.S. Capitol in Washington, D.C.; however, on rare occasions, they will convene for a joint session of Congress in the House chamber. For example, a joint session will be called to count electoral votes for presidential elections.