mathsection.com

4XgYX TIL about the Controversy surrounding the Four Color Theorem which states that every map can be colored using only four different colors. The remarkable theorem is the first that had to be proved using computer-assistance.
jNVea TIL about the Mathematician Fry Lewis Richardson who discovered that it is impossible to measure the length of coastlines in a meaningful manner. This so-called Coastline Paradox later led to the creation of the field of Fractal Geometry.
5YXjp TIL that in 1736 the mathematician Leonhard Euler was trying to find a way to cross every single one of the seven bridges of Königsberg exactly once. He realized that this was, in fact, impossible and based on that created a new area of mathematics called Graph Theory.