The Pontyunpronouncable aqueduct. Built by Robert Telford and now a World Heritage site. They clearly hadn't heard about elf 'n safety in 1795 but I am surprised we are not required to wear parachutes in this more safety conscious day and age.
The Anderton boat lift that takes you 50 feet up from the river Weaver to the Trent and Mersey. I think we really will invest in a couple of parachutes!