During the early 1980s, advanced sonar technology achieved high-resolution capabilities of scanning large areas deep in the ocean floor.
The device was often mounted on remotely operated recovery vehicles for archeological research.
Simultaneous development in computers, robotics, and fiber optics had practically made manned submersibles obsolete for the purpose, at least during the scanning phase.
Moreover, the underwater drone was (still is) much safer, easier, and more economically feasible compared to sending people to scavenge artifacts at the bottom of the sea.
In addition to the educational value, sophisticated sonar introduced a new opportunity for the more financially-driven adventurers of the seas: treasure hunters targeting shipwrecks loaded with fortune.
Among the most famous modern treasure hunters is Thomas G. Thompson, who successfully recovered a fraction of the wealth from the SS Central America.
The ship was carrying gold coins and bars worth an estimated $400 million when it sank off the Carolinas in 1857.
While Thompson made around $50 million from that, he is jailed for failing to distribute the money appropriately to the parties who contributed to the search.
10 /10 Sank Steamship
The SS Central America, also known as the Ship of Gold, set sail on September 3, 1857, from the port of Colon in Panama for New York City under the command of William Lewis Herndon.
Onboard the ship were 578 people, including 101 crews and at least 13 tons of gold. Off the Carolinas coast on September 9, the boat caught up with a Category 2 hurricane.
After a few days of struggling to get through heavy seas and winds, the SS Central America sank, taking 425 people and the gold to the bottom of the ocean.
9 /10 Richest Shipwreck
The sinking of the SS Central America stands today as the worst peacetime passenger ship disaster in the US.
Among the gold carried inside the ship, three tons prospected during the California Gold Rush.
Some would say the passengers collectively brought an equal amount. Rumors were suggesting that the ship also carried 15 tons of gold inside the secret Army cargo.
No one knows the exact amount of gold or how much money they are worth today, but for sure, SS Central America has been called the richest shipwreck ever.