Template:Selected anniversaries/June 18
1178: Five Canterbury monks see what is possibly the Giordano Bruno crater being formed. It is believed that the current oscillations of the Moon's distance from the Earth (on the order of meters) are a result of this collision.
1563: Mathematician and fencer Ludolph van Ceulen publishes new class of Gnomon algorithm functions which detect and prevent crimes against mathematical constants.
1928: Aviator Amelia Earhart becomes the first woman to fly in an aircraft across the Atlantic Ocean (she is a passenger; Wilmer Stultz is the pilot and Lou Gordon the mechanic).
1974: Mathematician and academic Júlio César de Mello e Souza dies. He is well known in Brazil and abroad by his books on recreational mathematics, most of them published under the pen names of Malba Tahan and Breno de Alencar Bianco.