What are some nice things to capture in a time-lapse video?

Recently I downloaded an app for my phone with which I can make time-lapse ‘videos’.
Now I made two of clouds moving by.
And in the spring I am planning to make some of growing flowers/plants.
Since I think it is fascinating I want to make use of it more but I can’t really think of other things that would be worth to capture and nice to view the finished result.
Can you maybe do a suggestion for subjects/phenomena to use for my app?