The rover named Perseverance landed on the surface of Mars. It is big, weighing about a ton, and since the atmosphere of Mars is so thin, parachutes are not sufficient to slow it enough to use airbags to cushion the final landing so they had to find another way.
Perseverance approached Mars at around 12,400 miles per hour, although when it hit the top of the atmosphere, a heatshield slowed it down to about a tenth of this speed. Then a supersonic parachute popped out of the rover to reduce its speed to a few hundred miles per hour.
At that point, descending under the parachute, Perseverance was still travelling far too fast to land safely. So it cut itself loose from the parachute and used rocket thrusters to slow down further. The thrusters allowed it to hover roughly 20 metres above the surface, before the rover was lowered by cables to the surface using a rocket platform called a sky crane.
Here is a video simulation of the landing.
You have to hand it to the engineers and scientists behind this project for a really impressive achievement.
You can see some of the first still images sent back here. There should be video soon too.