On Sunday, the world was in shock after it emerged that a tourist submarine seeking to visit the ruins of the Titanic went missing. 

The submarine carrying five people to the Titanic vanished deep in the Atlantic Ocean on Sunday night. The five are:  British billionaire Hamish Harding, French diver Paul-Henry Nargeolet, OceanGate CEO Stockton Rush, Pakistani businessman Shahzada Dawood and his 19-year-old son Suleman.

Rescue teams have been  searching for the vessel, which had a 96-hour oxygen supply when it began its journey Sunday morning. the oxygen is due to run out at 11am BST on Thursday, 22 June.

If the Titan and its five-person crew did arrive at the Titanic wreck, they will be located 3,800 metres (12,500ft) below the surface on the seabed.

Crews looking for the Titan submarine have heard additional “banging noises” on Wednesday morning — potential signs that the five passengers are alive — but have yet to locate the vessel lost in the Atlantic Ocean.

The noises were first detected Tuesday night and heard again on Wednesday morning by Canadian P3 planes, which are used for conducting surface and subsurface surveillance over water.

The search area has been widened to an area twice larger than the US state of Connecticut, and several noises – including reports of ‘banging’ – are being investigated by analysts and with remote operated vehicles.