Whaling, hunting of whales, originally for oil, meat, and baleen (whalebone), practiced since the 10th century. The Basques and Dutch hunted from land and pioneered methods of flensing (stripping of blubber) and boiling whale meat. U.S. whaling started in the 1600s, and whaling ports such as Nantucket and New Bedford, Mass., grew to great size in the 1700s. Whaling became safer for the hunters after the invention (1856) of harpoons with explosive heads that caused instantaneous death and avoided the dangerous pursuit of a wounded whale. From the 1800s whalers moved south in pursuit of the sperm whale. Development of factory ships that processed the catch on board facilitated longer expeditions. In the 20th century whaling has centered on Antarctic waters. Reconnaissance aircraft and electronic aids are now used. Whale products include oils, ambergris, spermaceti, meat, and bone meal. Despite the voluntary restrictions of the International Whaling Convention, whales are still overfished, and many species face extinction.