The National Congress complex is the most recognisable image of Brasília — a saucer-and-dome composition with twin office towers, anchoring the east end of the Esplanada. The dome (Senate) and the inverted bowl (Chamber of Deputies) face the great open Square of the Three Powers; the white twin towers between them rise from a low base of meeting rooms.
Free guided tours run on weekends and (with advance booking) on weekdays. The tour takes about an hour and goes inside both chambers, the President of the Senate's office, and the Salão Negro lobby — covered in dark Brazilian granite — that connects them.