On average, the ocean is 3,682m deep. That's about eight Empire State Buildings, stacked on top of each other. The deepest part is 11,030m––that's twenty-five Empire State Buildings.
It's estimated that there is over eighteen billion kilograms of gold hidden beneath our oceans. If it were possible to mine it, there would be enough gold for every person on the earth to own 2.5kg, worth almost $100,000.