Prince William has congratulated Sir David Attenborough on reaching a "remarkable milestone", as the broadcaster and environmentalist celebrated his 100th birthday. Sir David's seven-decade career was marked with a night of memories, live music and special guests at a special concert at London's Royal Albert Hall on Friday. "It is a rare privilege to celebrate a century of life," Prince William said, "but it is rarer still when that person has transformed the way we see the only home that we