South of Hoam Kiem lake there are a number of famous buildings. The Hanoi towers are built on the site of the infamous Hoa Lo prison, where many people were tortured and executed. The Trang Tien plaza is a newly built shopping complex. The Opera house, built in 1911 on a design of Francois Lagisquet, has been restored in 1997. It is one of the finest French colonial buildings in Hanoi.