Ambush is the best map, both sides of the 'tank road' have places to get on top of all the buildings.
All you have to do is jump accross the fence on each sides, and you can walk on top of all the buildings. If you fall down into the middle of the shanty buildings on one side, there is even a ladder to get you up onto the wall again - so obviously you're meant to get up there, just i havn't seen anyone else ever do it.
On Overgrown you can walk along that corrigated bridge and jump on top of the building that people sniper from - you can even walk all the way around the side.
On Crash you can get on top of the fence at the top of the trhee-storey building and jump off to one side and walk around the edge of the map at 30 feet up. You can also jump onto a certain roof (above the shop). you can also jump up to the ceiling in the garage where the car is.
On District you can jump on top of the marketplace roof, but nobody knows about the little balcony round the corner you can jump to where nobody ever looks.
On Strike there is another balcony you can hide in near the statue, just jump on the rubbish bins and walk along a wall. You can also walk around the back of the plant shop along the wall and around the building to jump onto a fence about 30 feet up.
On Backlot you cvan jump on the roof of the building in the middle, then jump off the railing to one side and land on top of a telegraph pole - you can hop onto two more telegraph poles and be 30 feet up in the air where nobody will look.
On Bog you can jump onto a car to get on top of a large container, as well as jumping on some boxes and hiding up a balcony. You can also jump on top of the fence and then onto a heating vent and hide 20 feet up a wall above a door.
On Bloc you can jump onto a stairway and climb up about 90 feet to the top of the stairs on the side of one building. (p.s what is the sword stuck in the rock supposed to mean!?

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erm.. thats about all i recall, apart from jumping on team mates heads, thats the only ones i know that you can do on your own and not have any oldcore modes where you can jump higher or anything.