A steep narrow ladder extends from the ground floor up 3 storeys into the attic, with bars instead of stairs, and a minimal railing, inside a mechanical room.

Ladder

The 'ladder of fear' for those who are height-phobic. There aren't even regular treads to climb - the treads are just two bars that you stand on, and the handrail only exists on the right-hand side. A fun climb, indeed.