Make sure you choose the ISS International Space Station that Google Maps has provided since July. You can explore the space inside ISS from the perspective of a European astronaut who has spent 6 months living here.
It may be a bit difficult to navigate between planets and Google Maps doesn't have a search engine when it comes to space, but going around to see what you can find will be interesting.
Part of Mars looks very detailed thanks to the planetary surface images taken from NASA's explorer car. The level of zooming and rotating around the planet is also limited, but what you will definitely see is something you have never seen before.