Europa is one of the moons of Jupiter. It is especially interesting because it is thought to have water oceans under it's icy surface which could potentially harbor life!
Source: NASA
When I was in primary school I used to dream of being able to visit Europa someday. The tidal forces from Jupiter keeping the sub-surface ocean warm enough to potentially harbor life was always fascinating to me.
I can't wait for the Clipper Mission, but I hope that we get a chance to send a submersible to explore the oceans in my lifetime.
The engineering feats to accomplish it would be some amazing accomplishments alone. 15 to 20 miles of ice, then having to deal with the pressure of the ocean? It's going to be amazing and I'd kill to be part of that problem solving experience