Climbing Into Cities
From atop a Wilderness hilltop, cities can be seen to contain homes, shops, churches and castles. By climbing over the wall into the city these can be discovered to be low-resolution props. The walls of homes and shops can be passed through, and buildings, doors, and gates are transparent from within. A good place to try this is to enter Cheydinhal from its southwest corner, where a hill rises nearly to the height of the walls. Two levels of paintbrushes are all that is required to gain the battlements and access the interior of the city.


Climbing out of Cities
In the same way it is possible to enter cities without using the gate, it is possible to exit them. It is even possible to do this without the Floating Paint Brushes glitch.


Anvil
Jump on the roof of the Abandoned House.
Jump onto the roof of Silgor Bradus' House.
Follow the chain of roofs: Pinarus Inventius' House then Newheim the Portly's.
Jump out of the city

Bravil
Jump onto the roof of S'Krivva's house from a nearby building.
Jump across the street onto the roof of the other building.
Jump onto the highest point you can.
Jump out of the city.

Bruma
Climb onto the roof of Olav's Tap and Tack.
From there jump along the roofs over the houses of Brotch Calus, J'Ghasta, and Helvius Cecias.
From the the chimney of Helvius Cecias' house you can jump onto the battlements.
From the battlements you can then either walk about a bit, or jump out of the city

Cheydinhal
Get onto the balcony outside Riverview.
Jump on the railing around the balcony and then onto the roof.
Jump out of the city

Chorrol
Jump on the low rock wall on the north side of the Fighters Guild.
Jump onto the wooden target then the overhang and the main roof.
From the chimney, jump onto the roof of the Mages Guild.
Get as close as possible to the chapel and jump onto it.
Head around to the north side of the chapel then jump onto the city wall and out.

Leyawiin
Get onto the short wall to the east of the Five Claws Lodge.
Jump onto the low roof of the lodge then get to the highest point.
Jump onto the city wall and out.

Entering the Imperial City Invasion Prior to Light the Dragonfires
By using enough paint brushes with the Floating Paint Brushes glitch, you can climb onto the rooftops around the Temple of the One (or onto the temple itself) in the Imperial City, and jump onto the temple (you will fall through the roof). Do not go through the main door when you are inside. Instead, you will find a door that is partly underground a few steps ahead of it; go into that one. You will find yourself in the invasion of the Imperial City that occurs during Light the Dragonfires. There is no use for this glitch, as none of the quest NPCs are with you, not even Mehrunes Dagon is there. Also, it is impossible to escape the Temple District and you cannot go back to where you came from, so it is highly recommended that you save before attempting this glitch. On the Xbox 360, during the Kvatch quest where Martin follows you, this can be used to get the main quest achievement very early but it is not wise to save afterward as it blocks the rest of the main quest achievements for that player.