That's a really tricky question to answer. I love visiting museums and galleries, but I also love physics. I see the beauty and art in everything around me, so I guess I'll go with science.
Just because I'm in a sharing (otherwise known as inebriated) mood... I'd choose the first too.
I'd choose a river rather than a lake. The lake is always still, never changing. The river is always moving onwards until it reaches the freedom of the ocean.