Worlds longest straight staircase inside a mountain

Worlds longest straight staircase? On the internet the most widespread answer is: Jacob's Ladder Stairs: 699 stairs Length: 281,6 metres (924 ft) Vertical meters: 183 metres (600 ft) Maximum incline 87 % (41°) Material: Concrete A staircase on an island somewhere in the middle of the Atlantic Ocean. A staircase leading from Jamestown, Saint Helena, up the side of Ladder Hill to Ladder Hill Fort. The name is a reference to the biblical Jacob's Ladder, a ladder extending to heaven. But is it the longest straight staircase? No. 

Worlds longest straight staircase

And probably Worlds longest staircase inside a mountain is:

Gaustabanen Stairs (Trappe)

Stairs: 3111 stairs Length: 1050 metres (3445 ft) Vertical meters: 650 metres (2133 feet) Maximum incline: 81 % (39°) Material: Wood A staircase inside Gaustatoppen mountain in Norway. Leading from the base station to the top station of a funicular. Going straight up. No landings, no turns. The stairs - as many other funicular stairs - are not normally accessible to the public, except for one day a year: The annual Gaustabanen stair running event. Gaustatoppen exterior. Gaustatoppen interior, Gaustabanen railway track and stairs (photo: Gaustabanen). Looking up the stairs, on left side of tunnel. Stairs seen looking down; tunnel looks brighter than in real life (photo: Gaustabanen). Map of the tunnel system.

Read more about stairs and long stairs (and Gaustabanen):

  Wikipedia: Stairs Gaustabanen Gaustabanen Trappeløb (interior stair photos: Gaustabanen)