KT, RM, SM, TN, TW, UB. • Bus route 20 runs from Walthamstow to Debden . 21 • There are 21 underground stations inside the Circle Line . • Tower Hamlets is named after the 21 Hamlets Of The Tower : Bednal Green, Blackwall, Bow, Bromley, East Smithfield, Hackney, Limehouse, Mile End,