In basketball, the rim is the equivalent to a "goal" in another sport. Players try to score into it, and it is made up of three important parts. There is the backboard, rim, and the net. The backboard is behind the rim and connects the whole apparatus to the ground with a vertical support system while the net is attached to and hangs below the rim. The NBA's regulation rim height is exactly 10 feet off the ground. The net hangs about a foot and a half below the rim (8.5 feet off the ground) and the backboard extends upwards to about 13 feet off the ground. (Below is an image of a basketball hoop).
The NBA's rim height of 10 feet is standard for all basketball levels from high school and up. Younger ages play with shorter rims to enable the players to reach the rim with their shots. The NBA rim is as tall as it is because many NBA players are 6'3" and taller, and they have no problem getting the ball to the rim. A 10-foot tall NBA basket is challenging for anyone to score on, but much less so, for NBA players such as LeBron James (who is 6'9") and Anthony Davis (who is 6'10").
The regulation distance for men's Division I in college is the same exact height as an NBA rim, which is 10 feet. In youth basketball, third and fourth grade players shoot on eight foot rims and fifth grade players shoot on nine foot rims. Sixth grade players and above shoot on 10 foot rims. The height of an international-sized rim is the same as college and the NBA, 10 feet off the ground. In the Gatorade League or G-League (previously called D-League), the rim measurement is exactly the same as the international, college and the NBA, 10 feet from the floor to the rim.
Ever since the creation of the sport in 1891 by Dr. James Naismith (the sport was originally called Basket Ball) the height of the rim for professional leagues always been 10 feet high. That is no different from the NBA, from its first season to now has maintained a 10 foot rim.