Who's the best climber in the world?
Adam Ondra is the one most consider as the best climber in the world.
He started climbing when he was just 3 years old, and onsighted a 7b+ when he was just 8 years old.
His climbing future was just as bright, and at that early age became one of the top names in the climbing community.
Over the course of less than 20 years, he has climbed over 1550 routes that are graded 8a and above, including the world's first ever proposed 9c. Out of those routes, he has onsighted over 720 of them.
He has had enormous success in climbing competitions, and has even competed in the first ever Olympic climbing event. Though he came in at 6th place and did not take home a gold medal, he is still considered to most people as the best climber in the world.
This question has been debated a lot, and will continue to be debated, as there are many other climbers that people consider to be the best, but by far Adam Ondra is the one the majority see as the best in the sport.