Bridges are a structure type in Dungeon Keeper and Dungeon Keeper 2. They are used for crossing both water and lava, allowing creatures that are normally unable to cross these areas to be able to reach new locations.
Dungeon Keeper
In Dungeon Keeper, Bridges can be placed on both Lava and Water and remain in place indefinitely (unless sold, for example), despite the fact it looks to be made out of wood. Bridges must be built in order for 
Imps to claim land on the opposite sides of bodies of lava and water. Imps cannot claim land that is not connected with a bridge. Additionally, Imps will not pick up corpses that are too far from your dungeon, so adding bridges may allow your Imps to get closer and help get knocked out heroes and/or enemy creatures into your reach.
Dungeon Keeper 2
In Dungeon Keeper 2 there are 2 types of bridges:
- The Wooden Bridge (will burn down if built on lava after a minute from construction);
- The Stone Bridge (immune to the burning effects from lava).
