When something is breathtaking, it means that it is extremely beautiful, astonishing, awesome, astounding, so much that it can knock the breath out of your lungs. There are so many ways one can have a breathtaking experience. Sometimes, when you see someone who is so gorgeous that you cannot explain it, it can be breathtaking.
Secondly, there are views that can be amazing, for example, view of an entire city from a particular spot on the mountaintop. This can create feelings of excitement and take your breath away. Again, one can have a breathtaking experience with a ride. It could be a boat ride of a beautiful Island, a ride of the city in a vintage car, or a visit to a cave with some hidden treasures.
What could be breathtaking to one person might not be to another person. However, you may not be able to tell what can be breathtaking to you until you experience it.