1) The first modern Olympic marathon race was held at the 1896 Olympics in Athens and has since become one of the most iconic and challenging events in athletics.

2) The first photograph of a black hole was captured in 2019 using a network of telescopes around the world.

3) The development of the World Wide Web Consortium (W3C) and web standards has ensured interoperability and compatibility across different web browsers and devices.

4) The ocean covers about 71% of the Earth's surface and contains roughly 97% of the planet's water.