London Underground ticketing London Underground ticketing The London Underground metro system of London, England uses a mix of paper and electronic smart-card ticketing. London Underground uses Transport for London's Travelcard zones to calculate fares, including fares on the Underground only. Travelcard Zone 1 is the most central, with a boundary just outside the Circle line and Travelcard Zone 6 is the most outlying zone covering any of Greater London and it includes London Heathrow Airport. All of Greater London is covered by zones 1 to 6. Tickets including zone 1 are usually more expensive than those involving only outer zones. The most popular
Attacks on the London Underground On 9 December, a van bomb partially detonated at the car park of Woodside Park station. No-one was injured but it caused evacuations and disruptions. A device exploded at an underground passageway at South Kensington station on 3 February 1993. On 20 December, a device exploded in a litter bin in Northfields station. On 21 December, coded bomb warnings from the IRA resulted in a paralysed London Underground system, as tens of thousands were evacuated from 100 tube stations during the morning rush hour. In 2005 two groups of Islamist extremists attacked a number of underground lines and bus routes