Private London Tour by Traditional Black Cab: City Sights from Above and Below. See top London sights from above and below ground on this private, 4-hour black cab tour! Guided by a knowledgeable and friendly driver, your tour includes a visit to London’s little-known underground tunnels beneath the River Thames, as well as visits to several vantage points around London for panoramic views. Climb the Monument to the Great Fire of London, see the dome of St Paul’s Cathedral and cross the River Thames by cable car. Book and Save 10% Off Private London Tour by Traditional Black Cab: City Sights from Above and Below.