Mars appears to have harbored life at one point. It probably lost it's magnetic field long ago due to the core drying out resulting in the unprotected atmosphere being blasted away by solar wind.
And that's just the Milky Way...
Funny some of the comments on there...ie the first one specifically 'stating' how impossible it would be to be visited by any intelligent life basing their theory on our own primitive benchmarks and 'rules' of space travel.
We are being visited and I have been abducted and probed. It's fun.