Calabarzon strategic importance, Corregidor is found at the mouth of Manila Bay and is under the jurisdiction of Cavite City. Laguna has rugged terrain, with narrow plains near the shores of Laguna de Bay and mountainous ranges further inland. Laguna de Bay is the largest lake in the Philippines, and is named after the town of Bay. Laguna is also home to Mount Makiling, a dormant volcano near Los Banos reputed for its mystical properties. There are also a lot of hot springs near the Makiling area, especially in San Pablo. Another famous landmark in Laguna are the Pagsanjan Falls, in
Arroyo de la Laguna Lake. With development of the valley starting in the 19th century, drainage alterations in this watershed reduced the lake to a watercourse now called the Arroyo de la Laguna. In the northern portion of the Arroyo de la Laguna catchment basin, the Tassajara Formation underlies Quaternary valley fill material. Contacts of these two formations are often indistinguishable due to similarities of physical characteristics. The prism of sediments identified as valley fill materials contains from eight to ten separate zones of sand and gravel separated by zones of silt and clay. Rapid development and other historic changes in the upper watershed