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.
Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.