The 55km bridge and tunnel linking Hong Kong to mainland China via Macau is set to open, years late.

Stretching more than 55km (34 miles), the Hong Kong–Zhuhai–Macau Bridge spans the Pearl River Delta and is an unparalleled engineering feat.

From end to end, including its two link roads, the bridge is about 20 times the length of San Francisco's Golden Gate Bridge.

The structure is designed to withstand earthquakes, the seasonal typhoons which tear through the region and accidental ship strikes.

To allow ships to continue passing through the estuary, the bridge plunges underwater for 6.7km midway, via two artificial islands.

Construction on the project began in 2009 but has been marred by delays and safety concerns. It has repeatedly overshot its budget, ultimately costing more than $20bn (£15.3bn).

The bridge has not only overshot budget and schedule but also taken a deadly toll on the workforce. Hong Kong and mainland Chinese authorities have each reported nine worker deaths during the work.

The bridge connects three very different parts of China - the two Special Administrative Regions of Macau and Hong Kong and the mainland. That means the project stretches across different legal and political systems

Buses and commercial vehicles will carry passengers and freight over the bridge. Local taxis are not allowed on it and only a few private cars will get a permit to cross. (BBC)