A British explorer. A father and son. An adventuring CEO. And a French pilot known as “Mr. Titanic.”

Those were the five men aboard the submersible that went missing near the wreckage of the Titanic on Sunday morning. They’re now dead after the US Coast Guard said debris found Thursday indicated their ship suffered a “catastrophic implosion.”

Coming from different backgrounds, they converged in St. John’s, Newfoundland, a Canadian city on the easternmost tip of North America, bound by a common dream of seeing the remains of the passenger ship that has been on the ocean floor since it sank in 1912.

“Our hearts are broken,” Explorers Club President Richard Garriott de Cayeux said in a statement. “Their memories will be a blessing and will continue to inspire us in the name of science and exploration.”

Stockton Rush

Stockton Rush, 61, founded the Everett, Washington-based OceanGate Inc., the company that owned the submersible craft, in 2009.

He had hoped to make the wreckage of the Titanic more accessible to scientists and visitors, coupling expeditions to the site with research efforts allowing passengers of varying scientific experience to contribute.

Rush, an alumnus of Princeton University and University of California, Berkeley, built upon inherited wealth through angel and venture investing. He became the youngest jet transport-rated pilot in the world in 1981, becoming a captain at the United Airlines Jet Training Institute at age 19, according to his biography on OceanGate’s website.

While he initially wanted to explore space, Rush said he realized his desire to discover new lifeforms and go where no man had gone before was more likely to be fulfilled through deep-sea exploration.

Rush, who was piloting the Titan, had come under scrutiny for his approach to safety with the experimental craft, which was subject to little regulatory oversight and required passengers to sign waivers before they boarded that repeatedly mentioned the possibility of death.

Hamish Harding

Hamish Harding was a British aviator and businessman who founded Dubai- and UK-based private equity company Action Group in 2022. The business oversees Action Aviation, an aircraft brokerage, management and financing company, of which Harding served as chairman.

The 58-year-old was an avid adventurer with previous experience in deep-sea exploration.

Harding spent a record 4 hours and 15 minutes on the sea floor of Challenger Deep in the Mariana Trench, the deepest part of the ocean, in 2021. At almost 11,000 meters (36,000 feet), the trench is two-and-a-half times as deep as the wreck of the Titanic. During that expedition, he also set the record for the longest distance traveled along the deepest part of the ocean.

Harding was described as a tremendously enthusiastic person with a passion for learning more about the world by Shane Lundgren, chief executive officer of Metolius Aviation Capital.

Lundgren helped Harding join the New York-based Explorers Club, a global group of adventurers and scientists. Lundgren said the British aviator had planned to visit the wreck of the Titanic last year, but the trip was canceled due to bad weather. “This was a big deal for him to finally get to go,” Lundgren said.

Harding graduated from the University of Cambridge with a degree in natural sciences and chemical engineering. He was married and had two children.

Read more: Titanic Sub Crew Dead After Vessel’s Catastrophic Implosion

Paul-Henry Nargeolet

Paul-Henry Nargeolet was a seasoned French pilot who participated in multiple expeditions to the Titanic wreck and was widely recognized as one of the world’s foremost experts on the site, earning the nickname “Mr. Titanic.” He was the director of underwater research for Experiential Media Group and RMS Titanic Inc.

The 77-year-old had completed dozens of submersible dives to the crash site, leading the first recovery expedition to the Titanic in 1987 after joining the French Research Institute for Exploitation of the Sea.

Nargeolet was incredibly modest and a very reassuring presence to those traveling alongside him, said filmmaker Alexander Lindsay, who accompanied him in expeditions to the site in the 1990s. Lindsay said Nargeolet gave explorers in cramped submersibles pep talks to comfort them if they felt claustrophobic. “If anyone knows what to do in a panicked situation, it’s him,” Lindsay said.

Nargeolet was born in Chamonix, France, and lived with his family in Africa for more than a decade. He spent 22 years in the French Navy, rising to the rank of commander, according to his biography on the E/M Group’s website.

Shahzada and Suleman Dawood

The Dawoods are a British father and son who are members of one of Pakistan’s most prominent families.

Shahzada was the vice chairman of Engro Corp., which has businesses stretching from fertilizers to power generation. The 48-year-old graduated from the University of Buckingham with a law degree and from Philadelphia University with a Master’s in textile marketing.

Suleman Dahwood, 19, was a student in the business school at University of Strathclyde in Glasgow, Scotland.

Both he and his father were lovers of science fiction and exploration, according to a statement from Engro.

The pair, along with the other three crew members, shared a deep passion for exploring and protecting the world’s oceans, OceanGate said in a statement Thursday.

“Our hearts are with these five souls and every member of their families during this tragic time,” according to the statement. “We grieve the loss of life and joy they brought to everyone they knew.”