On this day in 1994 - October 13th - NASA's Magellan mission ended with the spacecraft plunging into Venus.
Magellan - also referred to as the Venus Radar Mapper - was the first interplanetary mission to be launched from the Space Shuttle. It mapped the surface of Venus and measured the planetary gravitational field.
On this day in 1884 - October 13th - Greenwich in the United Kingdom was adopted as the prime meridian of the world.
There had been many prime meridians in use by countries around the world. But at the International Meridian Conference held in Washington DC, 25 maritime countries voted to adopt the Greenwich meridian as the longitude line of zero degrees.