The Dom Luís I Bridge is a double-deck metal arch bridge that spans the River Douro between the cities of Porto and Vila Nova de Gaia in Portugal. At its construction, its 172 metres span was the longest of its type in the world.
Construction took place between 1881 and 1886 with the bridge being built adjacent to an existing bridge which it replaced. The granite pillars of the original bridge are still in place, standing on the Ribeira like a pair of gate posts.
One of the notable features of the Ponte Dom Luís I is it's two levels; one on top of the arch and the other suspended below it. Both decks were initially intended to carry road traffic but these days the top carries the Porto Metro trains as well as having a pedestrian walkway. It is worth making the crossing on the upper level.
Today Luis I Bridge is part of the UNESCO World Heritage Site of Historic Centre of Oporto, Luiz I Bridge and Monastery of Serra do Pilar.
The Broch of Clickimin is a large and well preserved, though somewhat restored broch near Lerwick. Originally built on an island in Clickimin Loch (now increased in size by silting and drainage), it was approached by a stone causeway. The water-level in the loch was reduced in 1874, leaving the broch high and dry. The broch is situated within a walled enclosure and, unusually for brochs, features a large 'blockhouse' between the opening in the enclosure and the broch itself. Another unusual feature is a stone slab featuring sculptured footprints, located in the causeway which approached the site. Situated across the loch is the Clickimin Leisure Centre.