The last resting place of WW2 submarine the USS Grayback is found off the coast of Okinawa using high-tech undersea drones 75 years after the Japanese dropped a 500 pound bomb on it sending it 1,400ft down.

https://www.nytimes.com/2019/11/10/us/navy-submarine-missing-for-75-years-is-found-off-okinawa.html#:~:text=A%2075%2Dyear%2Dold%20mystery,The%20mystery%20began%20on%20Jan.

https://www.dailymail./news/article-7673005/Missing-WWII-submarine-USS-Grayback-75-years-went-missing.htmlco.uk