The human body gives off a very faint glow.

Japanese researchers using ultra-sensitive cameras in 2009 found that the body emits extremely weak visible light that rises and falls during the day. It is about a thousand times too faint for our eyes to see.

Aryabhata estimated pi to four decimal places.

In his seminal astronomical treatise Aryabhatiya written in 499 CE at age 23, ancient Indian mathematician and astronomer Aryabhata computed the ratio of a circle’s circumference to its diameter (pi, π) as 62,832 / 20,000, giving approximately 3.1416. Crucially, Aryabhata used the Sanskrit term asanna (‘approaching’ or ‘approximate’), demonstrating clear awareness that the value of π is irrational.

The world’s first website is still online.

Tim Berners-Lee published the first web page at CERN in 1991. CERN has restored it at its original address, info.cern.ch, where you can still read how the web was supposed to work.