This is an ancient teleport facility.
I use facilitys like this in my maps for fast travelling to far away regions.
It uses command blocks with the teleport command: /tp @p x y z
(x y z are the coordinates of the target area)
There is a mechanism to open the main door. Due to the vines it is a hidden one ;)
On the ground floor is a hall which represents the "landing area".
In my Maps the colour of the lights and floor are specific for every region.
On the upper floor, the "departing area" we got 6 alcoves with push-buttons. The buttons activate the command block behind the alcove.
The back can be reached by 2 small corridors. The lever to open these secret corridors can be found on the same floor.