https://www.youtube.com/watch?v=kBdrzCrKE6U
1834- Sandpaper is patented by Isaac Fischer Jr
https://youtu.be/M9GYlBmUMnA
1955- Discovery of diamond-bearing deposits at the Mirny Mine in Russia
https://youtu.be/UCcDVyaXRFQ
https://youtu.be/OjGkrwP7DMc
https://youtu.be/n5Iu4XH65aw
https://youtu.be/X3yrhLv8ApY
1938- the Helsinki Olympic Stadium, with a seating capacity of 39,784, opens in Finland.
https://youtu.be/S758wEniU0c