On the roof of the O2 Arena, one of London’s largest indoor venues, there’s a small cluster of very peculiar wind turbines. They look nothing like the tall, imposing ones that are increasingly ...

London (CNN) — On the roof of the O2 Arena, one of London’s largest indoor venues, there’s a small cluster of very peculiar wind turbines. They look nothing like the tall, imposing ones that are ...

CNN — London (CNN) — On the roof of the O2 Arena, one of London’s largest indoor venues, there’s a small cluster of very peculiar wind turbines. They look nothing like the tall, imposing ones that are ...