Chang'e 5!
Congratulations to the Chinese for the success of their Chang'e 5 lunar sample return mission!
The complexity of landing a robot on the moon and returning it safely to Earth is enormous. In contrast to the Apollo series of missions, which launched and returned inside of a week, Chang'e took a week to get to the moon, and two weeks to return. It's a nice optimization of fuel, and complicates thermal management.