In 393 AD, an earthquake and tsunami destroyed Olympia, Greece and the ancient Olympic Games came to an end. Around 1500 years later, Pierre De Couberdin revived the Olympic Games. The 1932 Los Angeles Olympics saw fewer athletes attend due to the economic impacts of the Great Depression. World War II caused the cancellation of the 1940 and 1944 Games. Terrorism remains a threat to Olympic security, but high levels of protection make attacks unlikely to succeed as planned. The 1972 Munich Games saw the tragic killing of 11 Israeli athletes after being taken hostage by Palestinian terrorists.