Inventions, firsts, and turning points tied to today’s date — each one sourced and dated.
A car-sized rover survived "seven minutes of terror" and a rocket-powered sky crane to reach Gale Crater.
A short newsgroup post invited anyone, anywhere to download the web's software and start linking the world.
At 8:15 a.m., a single uranium bomb leveled most of a city and opened the nuclear age.
