Progress on two major European skyscrapers may not represent the green shoots of economic recovery, but they help lighten the gloom. In London, pile work is due to start mid-month on the 310-m-tall "Shard," planned as Europe�s second-tallest building. And workers in Frankfurt are beginning to mobilize the planned Tower 185. Photo: Vivico Real Estate Workers begin mobilizing for Frankfurt Tower 185. Photo: London Bridge Quarter Ltd. If London's 310-m-tall "Shard" moves forward, it could Europe's second tallest building. With Middle Eastern backing, London Bridge Quarter Ltd., recently signed a construction contract with local Mace Ltd. for the estimated $1.5-billion
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.