Boring touristy photo here, but isn't it pretty? This is the Hermitage - a very famous and pretty museum on Palace Square which we took a large wander around on another day. Much more impressive was the square itself - which at night fills up with rollerbladers, skaters, guys on scooters and people just generally hanging out. In England this kind of gathering might be intimidating, especailly as the average age is probably about 16, but here everyone was incredibly friendly, and just out to have fun doing what they enjoy.
This is a top pick!