The first postage stamp was issued (1840) Known as the Penny Black, the first postage stamp for use in a public postal system was issued in Britain on this day. It cost a penny, and is now an extremely rare popular collector's item with philatelists.
The Chunnel opened. (1994) The Channel Tunnel, or Chunnel, officially opened on this day, connecting Britain and France for the first time since prehistory. It cost over $16 million US Dollars (USD) to build and is considered one of the Seven Wonders of the Modern World.
The Hindenburg exploded. (1937) It was one of the first major air disasters, and was even more dramatic because the crash was broadcast live on the radio. Thirty-six people died, and many others suffered serious burns and other injuries.
Roger Bannister broke the four-minute mile barrier. (1954) People had thought it was actually physically impossible to run a mile in under four minutes until Bannister did it in Oxford on this day. His record didn't last long — improvements in running techniques made the four-minute mile more common — but he was still the first person to prove it possible with a time of three minutes and 59.4 seconds.
President Franklin Roosevelt created the Works Progress Administration (WPA). (1933) Part of the "alphabet soup" of programs created by FDR, the WPA created over 3 million jobs, most of which were involved with public works like road building or restoring historical buildings.
The Hitler diaries were found to be a hoax. (1983) Snippets of the alleged diaries had been published in Stern a German magazine that bought them in secret for millions of dollars. Historians and researchers quickly found out they were a hoax after analyzing the diaries, finding that the materials used to make the diary were from the 1980s, not 1940s.
Pope John Paul II became the first pope to enter a mosque. (2001) John Paul II visited the Umayyad Mosque as part of a visit to Syria and delivered an address on the importance of peace between Christians and Muslims. He was also the first pope to make an official papal visit to a synagogue.
The final episode of Friends aired. (2004) The enormously popular show had run for over ten years, and over five million people tuned in to watch its finale.
The Magnum XL-200 became the first hypercoaster. (1989) It was the first complete circuit rollercoaster with a height of over 200 feet (70 meters), and sparked what is known as the roller coaster wars, as different parks began building higher and higher roller coasters.
Orson Welles was born. (1915) Welles was a hugely influential, though often controversial, radio and film star. He is best remembered for Citizen Kane and the radio broadcast The War of the Worlds, as well as for his distinctive, low voice.