Slightly less thrilling than a moon base and Mars exploration is deep-sea exploration. A next-generation robot will soon visit the deepest part of the Marinas trench (and therefore, the deepest part of the ocean.) I found this interesting:
"While the oceans cover two-thirds of the planet, the vast majority - 90% - are unexplored.
"We have better maps of Mars than we do of our own seabed, oceanographers say.
"But according to Professor Chris German, from the Southampton Oceanography Centre (SOC), UK, new underwater technologies will extend scientists' reach - soon - to all areas of the ocean floor.
"You could say that deep-sea exploration is the new space exploration," he said."