The wreckage from a Pan Am plane crash in the ocean 74 years ago that helped lead to requirements for the passenger safety briefings on every flight today has been found off the coast of Puerto Rico.

The talks flight attendants deliver about how to inflate a life vest or find the exits on a plane that are routine today were developed after 52 people perished aboard Pan Am’s Clipper Endeavor because they didn’t get off the plane before it sank. Explorers used an autonomous sonar drone to find the fuselage and tail of the DC-4 last month under 2,000 feet of water.