1) Serena Williams is an American professional tennis player widely regarded as one of the greatest athletes in the sport. She has won numerous Grand Slam titles and Olympic gold medals and has become an influential figure both on and off the tennis court.

2) The Paralympic Games, held immediately after the Olympic Games, showcase the athletic abilities of individuals with disabilities and promote inclusivity in sports.

3) The Amazon rainforest produces more than 20% of the world's oxygen.

4) The Serengeti National Park, located in Tanzania and extending into Kenya, is renowned for its vast savannahs, diverse wildlife, and the annual wildebeest migration. It is a UNESCO World Heritage site and a popular destination for safari enthusiasts and nature lovers.