The Cape Florida Light is a lighthouse on Cape Florida at the south end of Key Biscayne in Miami-Dade County, Florida. It was built in 1825 and operated, with interruptions, until 1878, when it was replaced by the Fowey Rocks lighthouse. The lighthouse was put back into use in 1978. The lighthouse marked a reef four miles (6 km or 7 km) off-shore, and still marks the Florida Channel, the deepest natural channel into Biscayne Bay. The construction contract called for a 65 foot (20 m) tall tower with walls of solid brick, five feet thick at the bottom tapering to two feet thick at the top. It was later found that the contractor had scrimped on materials and built hollow walls. In 1835 a major hurricane struck the island, damaging the lighthouse and the keeper's house, and putting the island under three feet of water.