1794: Maximilien Robespierre was sent to the guillotine during the French Revolution.
1821: Peru declared its independence from Spain.
1914: World War I began as Austria-Hungary declared war on Serbia.
1976: An earthquake devastated north China, killing 242,000 people.
2004: Francis Crick, who co-discovered the double-helix structure of DNA, died in San Diego at 88.