Titan was headed 12,500ft below the sea level to see the Titanic wreckage - how far is that?

The search mission for the missing Titan submarine is underway. The expedition was on voyage down 12,500 feet below the sea level to see the Titanic wreckage. 

The five people on bored of the vessel, named Titan, have been identified as Stockton Rush, the CEO of OceanGate Expeditions, the company behind the mission; British billionaire Hamish Harding, owner of Action Aviation; French dive expert Paul Henry Nargeolet; and prominent Pakistani businessman Shahzada Dawood and his son Suleman Dawood.

Due to the depths of the water there is reportedly no way of moving the men trapped inside from one sub to another. This means that the only way to rescue them is for a remotely operated vehicle (ROV) to  travel down the 12,500 feet and hook a cable to the sub and reeling it up to the surface. 

To put that distance into perspective 12,500 feet is 2.3 miles and 3.81 metres. The world's tallest building is the Burj Khalifa in Dubai at 2,716 feet and 0.5 miles (828 in metres). 

The Empire State Building in New York is 1,250 feet (380 metres) and around 0.2 miles. The Eiffel Tower is around 984 feet or (3 metres). 

The distance would be like walking from London’s St Paul’s Cathedral to Buckingham palace which is just over 2 miles and would take about 50 minutes.