Legendary diver known as 'Captain Nemo' dies

Nearly fifty years ago, Jacques Piccard dived almost seven miles below sea level, earning him the nickname "Captain Nemo" after the hero of Jules Verne's 20,000 Leagues Under the Sea. When he died on Saturday, aged 86, his incredible feat remained unchallenged as the deepest dive ever.

His son, Bertrand, said in a statement: "[Jacques] passed on to me a sense of curiosity, a desire to mistrust dogmas and common assumptions, a belief in free will, and confidence in the face of the unknown."

Piccard, who died at his home on Lake Geneva, Switzerland, was a legendary scientist and underwater explorer whose adventurous career led him to work for Nasa, to build pioneering submarines and, with his father, to develop the Trieste bathyscaphe – a vessel enabling humans to descend to then inconceivable depths.

Exploration was a family obsession. Jacques' father, Auguste, was the first to take a hot air balloon into the stratosphere, and his son, Bertrand, was the first to fly a hot air balloon around the world without stopping. But the feat that put Jacques Piccard in the history books was his 1960 dive. Piccard and US Navy Lieutenant Don Walsh broke records and changed perceptions of the ocean when they dived 35,800 feet [10,916 metres] into the Mariana Trench in the Pacific Ocean – the deepest point on the earth's crust.

The pair came across creatures that, previously, were not thought able to survive at such depths. "By far the most interesting find was the fish that came floating by our porthole," Piccard said after the dive. "We were astounded to find higher marine life forms down there at all." This discovery provided crucial evidence for prohibiting ocean dumping of nuclear waste, an important step for conservation.

Born in Brussels in 1922, Piccard went to university in Switzerland. He later taught economics, but abandoned it to help his father with the bathyscaphe project.

The father-son designed vessel took several trips into the Atlantic Ocean, but it flourished when it was taken on and redesigned by the US Navy.

After his record-breaking dive, Jacques went to work for Nasa and built four mid-depth submarines including the first for tourists – demonstrated at the 1964 Swiss National Exhibition when it carried 33,000 passengers to the bottom of Lake Geneva.

His son, Bertrand, was not only influenced by his father in terms of career, but used knowledge acquired from him to pursue his own projects. In 1999 he and his team drew on Jacques's experience of the Gulf Stream to use the jet stream to take them around the world in his hot air balloon.