On our second day in Paris, the first place we visited was Sainte-Chapelle. We got there slightly before it opened. I highly recommend going there early in the morning as it’s quite empty and the feeling is quite magical being one of the few people there(going right before closing could also work).
Afterward, we visited the nearby Conciergerie, which is where they kept Marie-Antoinette before she was executed. It wasn’t as interesting as I thought it would be, so if you don’t have a time, it’s not that big of a loss if you pass on it.
In the afternoon, it was time for us to visit the Eiffel Tower (make sure you book tickets before hand)! We arrived there quite early to take a lot of photos.
We went to the top of the Eiffel Tower, but if you are looking to save a few bucks, just going to the second floor would have been fine. The view is better and you wouldn’t have to wait in a ridiculously long line up to head to the top. But since I’ve flown all this way, it doesn’t hurt to experience going to the top of the Eiffel Tower anyway.