I'm surprised that noone has mentioned the Towering inferno (with Paul Newman).

They managed to slide down lengths of steel cable that were connected to the roofs of surrounding buildings.

A load of these in a lattice over the city streets would make an excellent provision for those needing to escape from above an impassible inferno.

It would also make it much easier to arrange the christmas decorations when december comes around. (Sorry, did I say December? I meant October.)

lox