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
Özkonak Underground City was probably built by the people of Byzantine Cappadocia, although the age is uncertain and could be older. The Özkonak Underground City was discovered in 1972 by a local farmer named Latif Acar, who was curious about where his excess crop water was disappearing to. Latif discovered an underground room which, when later excavated, revealed a whole city which could house 60,000 people for up to three months. Although only four floors are now open, the complex contains a total of ten floors, to a depth of 40m. Unlike the other underground cities in this area, there were holes above