We went to the moon in 69, and that's one of the most significant achievements of human history. As we too busy finding what is outside the earth, more than 80% of the ocean remains unexplored since the deepest ocean point was discovered in 1951. Located off the Marianas Islands coast in the Pacific Ocean, known today as the Mariana Trench, With a depth of 35,856 feet (10,929 meters)It is so deep that if you could put Mount Everest on the ocean floor, its summit still lies about a mile below the ocean surface.
In 1960 Jacques Piccard, a Swiss oceanographer, and engineer, designed a vehicle that can go into that depth is known as the Bathyscaphe, and discover amazing deep-sea life. Rolex's attach one of their experimental Deep-Sea watches to the Bathyscaphe and survive the pressures of 10,916 meters. This could be the first thing that started to the attention of deep-sea dive watches, consider in the 50s, most watches still can't be worn in water, and dedicate dive wristwatches like Rolex, Panerai, or Blancpain can go between 50-100m, so the race to the deepest has begun.
Both companies are presenting two very different approaches to the same problem. Rolex has many attempts as the watch crystal always pop out of the case while resurfacing due to the decompression; at this point, Rolex come up with the new technology and a real turning point, it's called the "Helium Escape Valve," a spring-loaded one-way value that opened to allow trapped gas to equalize, Rolex named the watch "Sea-Dweller."
On the other hand, Omega developed something entirely new, different case; different style starts from the ground up, it was overbuilt and went beyond the testing requirement. Omega name the watch "ProPlof" or 'Plongeur Professionnel' in french, meaning professional diver; the watch went double the 600m requirement and didn't need any Helium Escape Valve because the case is entirely made from one piece of steel and the only way to take the movement out is through to the front.
Both did the same job in the end, but Rolex did it on time and can supply the growing member of the COMEX by using the same existing design from the Submariner; Omega, on the other hand, come up short because it is an entirely new watch, it takes far more investment in time and technology, some say Omega didn't make any profit on the ProPlof because of the exceeding investment in developing. Omega has built the ProPlof for purpose and less commercial success in mind aiming at the best Dive watch in that time, sadly it doesn't get into the mass, Omega has won the Battle, but Rolex has won the war.