The entrance to the catacombs are located in Lumbridge cemetery. The Blood Pact must be completed in order to be able to access the lower level of the dungeon. The monsters are located at the bottom of the dungeon and can be accessed by the stairs in the room where Reese is defeated in "The Blood Pact" (revealed after the altar collapses). The Catacombs contain various monsters that make training extremely easy for low-levelled players. It is no longer detrimental to 1 Defence pures as the defence lamp that is awarded from the quest may safely be destroyed.