April 10

837 - Halley's Comet makes its closest approach to Earth at a distance equal to 0.0342 AU (5.1 million kilometers/3.2 million miles).
1815 - The Mount Tambora volcano begins a three-month-long eruption. The eruption ultimately kills 71,000 people and affects Earth's climate for the next two years.
1912 - RMS Titanic sets sail from Southampton, England on her maiden and only voyage.
1995 - The world's first national DNA database begins operations in the UK.
2019 - Scientists from the Event Horizon Telescope project announce the first ever image of a black hole, which was located in the center of the M87 galaxy.