In ZOO, to get in the aquarium, you have to get on the snack bar, and jump off onto the elephants neck while holding "Y".
In SAN FRANCISCO, to get the locked mission(Save Painter Niel), you first of all, grind the birds off the rail for him. Do it again, and the rail will snap, leaving Niel hanging above a shark. To beat the mission, simply grind the cable wrapped around the ball in front of you when you start.
Also in SAN FRANCISCO, to beat the pro callenge "grind the blockers", go against the wall near the 'spine transfer transfer' until you see a red button against the wall. WallRide it and hurry to grind 1 of the ledges. Now repeat and grind up the 2nd ledge.
PEACE!!!!!!!!!!!!!!!!!!!!!!!!!!
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