Richard Hammond reveals the ingenious engineering required to transport one of the most potentially hazardous cargoes in the world in some of the biggest vessels afloat. The huge ships, bigger than the Titanic, carry enough fuel to heat a city the size of London for a week - the energy equivalent of 55 Hiroshima atom bombs. Shipping this potentially volatile cargo required engineering solutions inspired by cutlery, mid-air refuelling and fire engines.