The Thames Barrier is a large movable flood defense system located on the River Thames in London. It was built to protect the city from rising tides and storm surges, which can cause flooding. The barrier consists of several giant gates that can be raised or lowered depending on the water levels, ensuring the safety of the surrounding areas. Constructed between 1974 and 1984, the Thames Barrier is one of the largest of its kind in the world. It plays a crucial role in safeguarding important landmarks, including the Houses of Parliament and the London Eye, from potential flood damage.