Going underground in London luxury basements

Updated 7:13 AM ET, Fri January 24, 2014
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Luxury basements are an increasingly common addition to high-end properties in London. The number of dig-down projects has increased by more than 500% over the last 10 years in the borough of Chelsea and Kensington alone. Courtesy London Basement
Swimming pools, bowling alleys, gyms, saunas and games rooms are some of the most popular features of basement extensions. Courtesy London Basement
Tight space and strict planning laws dictate that the facade of London neighborhoods must maintain their original character. This has led to residents extending beneath their properties instead of building outwards and upwards. Courtesy London Basement
A luxury basement lounge in the plush Hampstead district of London. Underground extensions are now becoming increasingly common in more modest neighborhoods such as Hammersmith, Clapham and Wandsworth. Courtesy London Basement
On the outside, this house in a quiet Fulham street seems to be exactly like it's neighbors. Eoghan Macguire
On the inside, however, a large basement extension hosts a lounge, bathroom, laundry room and spare bedroom. Eoghan Macguire
A stylish home cinema in a London basement added by expert dig-down company, London Basement. Courtesy London Basement
Most extensions drop one or two floors beneath the original house, however, some extravagant projects have been known to go as far as five floors down. These developments are the exception rather than the rule, however. Courtesy London Basement