The Puente Romano (Spanish for Roman Bridge) is a Roman bridge over the Guadiana River at Mérida.
It is the world's longest (in terms of distance) surviving bridge from ancient times, having once featured an estimated overall length of 755 m with 62 spans. Today, there are 60 spans (three of which are buried on the southern bank) on a length of 721 m between the abutments. Including the approaches, the structure totals 790 m. It is still in use, but was pedestrianized in 1991 as road traffic was redirected to use the nearby Lusitania Bridge.
Annexed to the bridge is the Alcazaba of Mérida, a Moorish fortification built in 835. Close to the remains of the Acueducto de los Milagros, there exists another Roman bridge at Mérida, the much smaller Puente de Albarregas.
References: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.