Cable-stayed bridge support the bridge deck. Unlike other cable-stayed types, this bridge exerts considerable overturning force upon its foundation and the spar must resist the bending caused by the cables, as the cable forces are not balanced by opposing cables. The spar of this particular bridge forms the gnomon of a large garden sundial. Related bridges by the architect Santiago Calatrava include the Puente de la Mujer (2001), Sundial Bridge (2004), Chords Bridge (2008), and Assut de l'Or Bridge (2008). Cable-stayed bridges with more than three spans involve significantly more challenging designs than do 2-span or 3-span structures. In a 2-span or
Pontoon (boat) of the world, especially in Africa. Pontoon ferries may be motorised, such as the Kazungula Ferry across the Zambezi River, or powered by another boat, or pulled by cables. A type of ferry known as the cable ferry ("punts" was what they were called in the medieval times and in modern Australia and New Zealand) pull themselves across a river using a motor or human power applied to the cable, which also guides the pontoon. Pontoons may support a platform, creating a raft. A raft supporting a house-like structure is a houseboat. The flotation tubes of rigid-hulled inflatable boats are