The monument commemorates the approval by referendum of the National Charter, which established a parliamentary monarchy. The names of some 220,000 citizens registered to vote at the time of the referendum are engraved on the outer walls. A moving place for Bahrainis, it might not merit the attention of foreign visitors were it not for a fascinating museum tracing the country's history and achievements. A tall concrete spire marks the building for miles around. It serves as the style for a monumental sundial that occupies the centre of the building.