Concealed wheelchair access

YouTube link.

"The company has installed hundreds of these lifts into all sorts of buildings and structures, from the Kensington Palace to Cambridge University. Many of the buildings in which the lifts have been placed are centuries old, with historic facades and entries preservationists hoped to keep intact. The Sesame retractible staircase blends so well, you can hardly tell the spaces have been altered..."

I like the fact that there's a temporary anti-rollback ridge after it goes up.