Catwalks hang over a section of the newly constructed eastern span of the San Francisco-Oakland Bay Bridge during a media tour of the self-anchored suspension span tower on August 29, 2011 in Oakland, California. Contruction crews have erected twelve foot wide catwalks that connect to the San Francisco-Oakland Bay Bridge self-anchored suspension span's tower and crews will begin to lay the nearly one mile of main cable beginning in early 2012. The bridge has been under constrution since 2002 with an estimated price tag of $6.3 billion and will have the world's tallest Self-Anchored Suspension (SAS) tower once completed. (Photo by Justin Sullivan/Getty Images)

The Dragon Bridge (Vietnamese: Cầu Rồng) is a bridge over the River Hàn at Da Nang, Vietnam. Construction of the bridge began on 19 July 2009 (the same day as the inauguration of the nearby Thuận Phước Bridge) when the Prime Minister of Vietnam Nguyen Tan Dung and many high-ranking government officials attended the groundbreaking ceremony. Dragon Bridge is 666m long, 37.5m wide and has six lanes for traffic. It opened to traffic on March 29, 2013, at a cost os nearly VND 1.5 trillion dong (US$88m). The bridge was designed by the US-based Ammann & Whitney Consulting Engineers with Louis Berger Group. Construction was undertaken by Company No. 508, an affiliate of Civil Construction Engineering Corporation No.5, and Bridge Company No. 75.

The Capilano Suspension Bridge is a simple suspension bridge crossing the Capilano River in the District of North Vancouver, British Columbia, Canada. The current bridge is 140 metres (460 ft) long and 70 metres (230 ft) above the river. It is part of a private facility, with an admission fee, and draws over 800,000 visitors a year.

People stop to look at the thousands of so-called “love locks”, or “love padlocks”, that hang from a fence across the Hohenzollernbruecke bridge on September 13, 2011 in Cologne, Germany. Love locks are a growing phenomenon in cities across Europe and are meant by the couples who leave them behind as a symbol of their powerful and undying love for one another. (Photo by Dennis Grombkowski/Getty Images)

A plane passes the Full moon as it rises over Albert Bridge on February 7, 2012 in London, England. Albert Bridge is said to be one of the most romantic bridges in London, and will be the start point for the flotilla of boats that will make their way along the Thames as part of the Queen's Diamond Jubilee celebration. (Photo by Dan Kitwood/Getty Images)

Trainees of the Tianjiao Special Guard/Security Consultant bodyguard training camp watch their instructor use a scarf to cover a student's head during a demonstration of close-quarter combat skills at a special course on flight safety inside a scale model of a passenger jet at a flight attendant training centre on the outskirts of Beijing, March 18, 2014. Inspired by the missing Malaysia Airlines Flight MH370, the company wanted to emphasize the importance of aviation safety by teaching their trainees emergency evacuation procedures and close-quarter combat skills to handle situations such as natural disasters and plane hijacks, according to the company. (Photo by Jason Lee/Reuters)

The Brooklyn Bridge is seen after a crane pulled by a tug boat on the East River slammed into scaffolding beneath the Bridge on March 13, 2012 in New York, NY. According to reports, no damage was done to the structure of the bridge. (Photo by Allison Joyce/Getty Images)

Pedestrians and traffic cross Tower Bridge as viewed through a glass viewing platform on the high-level Walkways during a preview to launch the new viewing experience at the Tower Bridge Exhibition centre in London on November 10, 2014. The new glass flooring at the Tower Bridge Exhibition 42 metres above the river Thames will allow visitors to gaze down on the bridge and river and allow them to experience the bridge opening from above. (Photo by Andrew Cowie/AFP Photo)