Tony Hawk's Underground 2: World Destruction Tour Unlockables

Easy High Score In Barcelona
Ok so pretty close to where you start you'll find the arcade machine. Go to it, and when you start turn right, then go up the green ramp to get some speed. Then, when you come back down turn a little bit then do rail rated challenge, and make sure you grind the rail on the balcony all the way, then at the end of it jump off and do a kickflip/double kickflip. This will get you about 20,000 points. Do this twice and you'll have the high score, and with time to spare. Hope this helps!

(IMPORTANT NOTE: This will only work if you've already done rail rated challenge!!!)

And here's some extra secret areas and stuff like that below.
UnlockableHow to unlock
Boston: Cannon Grind Of DestructionLight your board on fire, then grind one of the cannons. Then grind the other cannon while the first is still lit up.
Barcelona: Ole. Do I Really Have To Say More?This also unlocks the bull fighter. Get some tomatoes, then somewhere around the map you'll find a guy throwing tomatoes at a cage with a bull in it. Throw a few tomatoes, and the bull will break out of its cage.
New Orleans: Raise The Dead(This is also a goal, and unlocks the voodoo doctor) Go to the right side of the map, then go in the cemetery. There'll be 5 crypts, each with skulls on them. Knock all the skulls off the crypts, and the voodoo doctor will come and raise the dead, turning Nawlins into an undead wasteland.
Australia: Construction Is Destructive(This is yet another goal, 2 actually, and unlocks... well, i forgot his name) Go to the area with the construction workers. Do a natas spin on the fire hydrant for a certain amount of time, and it'll open up a new area. Go in there, then follow the cave, and you'll find a guy in a go kart. Then, get him, and grind on the crane thing.
Pro Skater: Escape 2 Worlds, And Get Stuck In H3llGo up the area with the aliens meditating, but don't go to them. Once you go through the door, go left. You'll be in an area with 2 green rails. Grind 1 of them to the end, then sticker slap the red panel. Go back and do it on the other side. This will open a portal to a Mayan temple. Once there, graffiti tag on the five idol statues in the walls. 3 are inside, and 2 are outside. Then, it'll open another portal, go in that one, and you'll be in H-E-Double hockey sticks. Then, if you grind the ribs at the end of that, and sticker slap the poles in a certain area, it'll open the giant demon statue's mouth. Go in it, and you'll be in a room. Through a door in that room, you'll see the devil.
The Triangle: Alien StudiesIn The Triangle, there's a lot of weird CRAP scattered around the place. And in the middle of all this weird junk, there's 2 or 3 helicopters, 1 of them has 3 white and red missiles, grind a certain one of those missiles, and it'll fire all 3. 2 at the mountain, and 1 at a halfpipe. Then, go in the mountain, and there will be 3 windows, each with aliens doing different activities.
Los Angeles: Bridge DestructionThere will be 4 special metal rails called "quake rails", and they're all fairly near eachother. So grind those 4, and it will start an earthquake.