Roger Federer chats with children during his trip to Zambia.

Roger Federer interacts with children during a visit to Zambia.

Roger Federer takes a break to chat with a local during a trip to Zambia.

Roger Federer plays soccer with children during a visit to Zambia.

Roger Federer takes time to visit school children during a trip to Zambia.

Roger Federer instructs a group of school children during a visit to Zambia.

Roger Federer works with local partners in Zambia and elsewhere around the world to improve children's lives.

Roger Federer has his share of support during his match against Thanasi Kokkinakis at the Miami Open presented to Itau.

Roger Federer takes a moment to collect himself during his second-round match against Thanasi Kokkinakis at the Miami Open presented by Itau.

Roger Federer will hand the No. 1 ATP Ranking back to Rafael Nadal on April 2.

Roger Federer must reach the quarter-finals in Miami to hold onto the No. 1 ATP Ranking.

Defending champion Roger Federer will contest his 17th Miami Open.

Roger Federer fans show their support from the stands during his match against Juan Martin del Potro at Indian Wells.

Roger Federer loses his first match of the season on Sunday against Juan Martin del Potro during the BNP Paribas Open final.

Roger Federer catches his breath in between games during his BNP Paribas Open final match against Juan Martin del Potro on Sunday.

Roger Federer launches a serve during his BNP Paribas Open final match against Juan Martin del Potro on Sunday.

Roger Federer rips through a forehand during his final match against Juan Martin del Potro at Indian Wells on Sunday.

Rod Laver presents Roger Federer with a special token of appreciation following his semi-final win at the BNP Paribas Open.

Roger Federer reached his eighth final at the BNP Paribas Open with his semi-final win over Borna Coric.

Roger Federer improves to a personal-best 17-0 to start a season with a gritty three-set win over Borna Coric to reach the BNP Paribas Open final.

Roger Federer is bidding to reach his eighth final in Indian Wells.

Roger Federer congratulates Tommy Haas on his career as the former World No. 2 announces his retirement Thursday night in Indian Wells.

Roger Federer is going for his sixth BNP Paribas Open title this week in Indian Wells.

Roger Federer will face Hyeon Chung for the second time when the pair squares off in the Indian Wells quarter-finals.

Roger Federer slices into a backhand during his fourth-round match against Jeremy Chardy at the BNP Paribas Open on Wednesday.