Britain's Prince Charles, Prince of Wales (L) and Britain's Camilla, Duchess of Cornwall (R) press the button to officially open the The National Grid's London Power Tunnels project at the National Grid Substation, Seven Sisters Road, in London on February 7, 2018. The Prince of Wales and The Duchess of Cornwall officially opened The National Grid's London Power Tunnels project, a 32km electricity superhighway deep below London's streets supplying electricity to the capital. / Getty Images / POOL / Chris Jackson