While setbacks and delays are common in the construction industry, certain projects stand out from the rest of the pack for the sheer amount of time and money they needed to finally reach completion.

Here are eight of the world’s most costly and time-consuming construction projects – some of which still remain unfinished – arranged in order of the number of years it took (or is still taking) to bring them to fruition.

World Island dubai

World Island. 

Location: Dubai, United Arab Emirates. Construction time: Ten years and counting.

This epic water resort was first envisioned by Sheikh Mohammed back in 2003, whose support for the project as Dubai’s ruler enabled it to commence almost immediately. The project is comprised of over 300 artificial islands situated in the Persian Gulf coast, with total costs estimated at $14 billion. While 60 per cent of the islands in the archipelago were sold by 2008, the GFC has scuppered subsequent progress, and many of the islands are still wholly undeveloped. Rumor has it that some of the islands are already sinking.

The Eastern Span Replacement of the San Francisco-Oakland Bay Bridge.

Location: California. Construction time: 11 years.

San Francisco-Oakland Bay Bridge

The construction of this 624-metre self-anchored suspension bridge was prompted by the occurrence in 1989 of the 6.9 magnitude Loma Prieta earthquake, which caused part of the original bridge’s unsafe cantilevered portion to collapse.

Construction on what is currently the world’s widest bridge, as well as California’s biggest ever public works project, only began in 2002, with the finishing date set for 2007. A slew of problems quickly put the project over budget and behind schedule, and the bridge only opened to traffic in September of this year.

The Big Dig”

Location: Boston. Construction Time: 16 years.

"The Big Dig"

The Boston Central Artery/Tunnel Project is a 5.6-kilometre tunnel designed to alter the route of Beantown’s portion of the interstate highway.  The project was riddled with problems, including defective designs, the challenge of working around operating subway tunnels, and the discovery of sunken ships and historic homes buried in the earth which barred the tunnel’s path. The project was completed in December 2007 after running nine years overdue, and holds the title of America’s most expensive highway project, with a final price tag of $14.6 billion.

The Sydney Opera House.

Location: Sydney, Australia. Construction time: 15 years.

The Sydney Opera House. Danish architect Jorn Utzon won the international architecture competition for the Sydney Opera House in 1957 with a strikingly original design. Work on the project commenced in the following year, with Utzon made responsible for directing construction.

The remaining course of the project’s development would not run so swiftly or smooth, however, and the Sydney Opera House only reached formal completion 15 years subsequently in 1973 at a total cost of $102 million – 10 years late and more than 14 times over budget.

Watts Bar Nuclear Power Plant.

Location: East Tennessee, USA. Construction time: 43 years (expected).

Watts Bar Nuclear Power Plant.

Work on the plant first began three decades ago in 1973. It took more than 20 years for the first of the plant’s two nuclear reactors – a Westinghouse pressurized water reactor, to go into operation, commencing supply of power in 1996.

The second reactor still remains incomplete, however, as the Tennessee Valley Authority brought work on it to a halt in 1988 due to reduced demand for energy, despite 80 per cent of construction already being finished. The project was revived in 2007 as a result of recent gains in demand for energy, with operation slated to begin in December 2015.

Second Avenue Subway

Location: New York City. Time from conception to completion: 87 years (expected).

Second Avenue Subway

The Second Avenue Subway project has been on the books since prior to the Second World War, and first became a plan project in 1929. A string of disruptions and funding shortages have since led to the project’s interminable delay over a period of more than eight decades.

The project is now well on its way toward completion, with a tunnel design by engineering firms AECOM and Arup, and construction management in the hands of Parsons Brinckerhoff. The 13.7-kilometre line is expected to be finished by December 2016, by which time its total cost will likely be in excess of $17 billion.

The Sagrada Familia

Location: Barcelona, Spain. Construction time: 131 years and counting.

The Sagrada Familia

This art nouveau church in the Spanish capital was designed by renowned Catalan architect Antoni Gaudi in 1883. Work on the project was still unfinished when he died in 1926, more than four decades after construction first commenced.  In fact work on the project still hasn’t ended more over a century later – the church currently remains only half complete, and has a tentative finishing date of 2026.

Upon completion, the building will be the tallest church in the world, with a 520-foot spiral adorning the dome of its basilica.

The Chunnel.

Location: The English Channel. Time from conception to completion: 192 years.

The Chunnel.

While the Chunnel only took about six years to build, the concept of a cross-Channel fixed link was first floated at the start of the 19th century in 1802, just prior to the commencement of open conflict between Britain and Napoleonic France. When it was belatedly realized nearly two centuries later, the project ran a staggering 80 per cent over budget, with a final price tag of $7.48 billion.