Here's an idea.

There are some fantastically dramatic landscapes here on Earth, and many look almost dream-like when seen from above! This would be a great excersize in colour, contour (anything) and breaking the chains of what are considered to be "Rules" of mapping, how rivers should flow, how mountains should form. Here are two examples which I found within less than 20 seconds.

https://www.google.co.uk/maps/@16.07.../data=!3m1!1e3

https://www.google.co.uk/maps/@31.03.../data=!3m1!1e3

It doesn't matter where you decide to look, you'll find something. The challenge is to draw it in a way that shows what it is you like about that lanscape! So if it's soft sand dunes, draw it in a soft way, or if it's the colour you like, draw it using only colour!