This is the day the Unix clock began (or December 31, 1969 if you live behind UTC 😉).

At 6:36:57 PM UTC, the date in ISO 8601 format (1973-10-17) within the time digits (119731017) appeared for the first time.

Unix time reached 1,000,000,000 seconds at 1:46:40 AM UTC. The Danish UNIX User Group celebrated this in Copenhagen, Denmark.

At 11:31:30 PM UTC, the digits of the time were 1234567890. This was celebrated worldwide, and even Google had a doodle for it.

Unix time will reach 2,000,000,000 seconds at 3:33:20 AM UTC.

Also known as the year 2038 problem, clocks running on a 32-bit signed integer will flip from 3:14:08 AM UTC on this day to 8:45:52 PM UTC on December 13, 1901. Therefore, values only from -2,147,483,648 to 2,147,483,647 for the second are supported.