According to Wikipedia these are some of the most extreme stairways in the world:
· The longest stairway is listed by Guinness Book of Records as the service stairway for the Niesenbahn funicular railway near Spiez, Switzerland, with 11,674 steps and a height of 1669 m (5476 ft). The stairs are employee-only.
· A flight of 7,200 steps (including inner temple steps), with 6,293 Official Mountain Walkway Steps, leads up the East Peak of Mount Tai in China.
· The Ha'ikû Stairs, on the island of Oahu, Hawaii, are approximately 4,000 steps which climb nearly 1/2 of a mile. Originally used to access longwire radio radio antennas which were strung high above the Ha'ikû Valley, between Honolulu and Kâne'ohe, they are closed to hikers.
· The Flørli stairs, in Lysefjorden, Norway, have 4,444 wooden steps which climb from sea level to 740 meters. It is a maintenance stairway for the water pipeline to the old Flørli hydro plant. The hydro plant is now closed down, and the stairs are open to the public. The stairway is claimed to be the longest wooden stairway in the world. For more info: http://www.lysefjordeninfo.no/en/
Let me know if you visit any of these extreme stairways!