What hit Russia in Feb was actually a meteorite, which is a any object that has crossed into the atmosphere of another object and impacted on its surface, aka in our case, Earth. In contrast an asteroid is a large rocky-like object orbiting in space, almost like a really tiny planet.
The meteorite that hit Russia in Feb was one of the largest meteorites to ever hit Earth, at over 55 feet in diameter. On entering the Earth’s atmosphere, it probably did disintegrate alright but because it was just so large, a lot of it still remaining after passing through the atmosphere, hence it landed on Earth in such good condition.
Cool, excellent answer Karen. Some of these meteorites also explode because they squeeze / compress air in front of them before they actually hit the ground. This causes the object to explode just above the ground, which usually causes much greater damage than the rock and ice itself. Have a look at some of the photos online to see the number of trees it levelled! Spectacular, and the chances of it hitting a city and VERY small.