This is proof of one big thing: Rich people aren’t rich because they’re smarter.

A massive search and rescue operation is under way in the mid Atlantic after a tourist submarine went missing during a dive to Titanic’s wreck on Sunday.

Contact with the small sub was lost about an hour and 45 minutes into its dive, the US Coast Guard said.

Tour firm OceanGate said all options were being explored to rescue the five people onboard.

Tickets cost $250,000 (£195,000) for an eight-day trip including dives to the wreck at a depth of 3,800m (12,500ft).

Government agencies, the US and Canadian navies and commercial deep-sea firms are helping the rescue operation, officials said.

Titanic’s wreck lies some 435 miles (700km) south of St John’s, Newfoundland, though the rescue mission is being run from Boston, Massachusetts.

The missing craft is believed to be OceanGate’s Titan submersible, a truck-sized sub that holds five people and usually dives with a four-day emergency supply of oxygen.

On Monday afternoon, Rear Adm John Mauger of the US Coast Guard told a news conference: “We anticipate there is somewhere between 70 and the full 96 hours available at this point.”

He also said that two aircraft, a submarine and sonar buoys were involved in the search for the vessel but noted the area in which the search is taking place was “remote”, making operations difficult.