Fireworks explode above the Bosphorus Strait in Istanbul on Tuesday, October 29, during the anniversary of the declaration of the Turkish Republic. On Tuesday, Turkey formally opened the world's first sea tunnel connecting two continents. The Marmaray links Istanbul's European and Asian sides under the Bosphorus. 
People travel from the Uskudar station to the Yenikapi station on the day of the tunnel's inauguration. 
Turkish President Abdullah Gul, seated right, listens to a driver's explanations in the cabin of a Marmaray train Tuesday. Also in the cabin are Turkish Prime Minister Recep Tayyip Erdogan, behind Gul in the green tie; Somali President Hasan Sheikh Mahmud, second from right; and Japanese Prime Minister Shinzo Abe, far right. 
Erdogan enters the train's cabin along with other dignitaries. Erdogan said the underwater railway "connects history and future, past and the future, as well as connecting continents. Marmaray connects people, nations and countries." 
Gul enters the Marmaray station during the inauguration ceremony. 
A Turkish train driver stands at a Marmaray station ahead of the inauguration ceremony. The Marmaray name combines the Sea of Marmara with "ray," which means rail in Turkish. 
A worker stands next to escalators Monday at the Uskudar Marmaray station in Istanbul. The rail system is expected to have a capacity of 1.5 million people a day, connecting Europe and Asia in about four minutes. 
A driver inspects a train before the opening. The Marmaray project, part of the Turkish government's plan to expand the country's economy, cost $4.5 billion. 
A man stands near the Bosphorus on Monday in Istanbul. 
Employees work on the Marmaray tunnel April 18. 
The Marmaray is being described as a vital link on the modern Silk Road, which will provide seamless rail transport from Turkey to China. - Turkey's state railway confirms reports there had been a power outage in the tunnel system
- Passengers hitting emergency buttons prompted "emergency situation procedures," it says
- Passenger volume caused train to skip one of the stops on its transcontinental route
(CNN) -- Istanbul's new transcontinental train tunnel under the Bosphorus Strait had a bumpy first day of operation, a day after Turkey's Prime Minister called it a "project for whole humanity" at an inaugural ceremony.
On Wednesday, Turkey's state railway confirmed reports there had been a power outage in the tunnel system.
"Emergency situation procedures" were also carried out multiple times, the agency said in a statement posted online, because passengers hit emergency buttons aboard the trains.
Turkish journalists complained of being barred from entry into the railway system after the breakdowns took place.
Tunnel in Turkey links Europe and Asia 
The challenges of connecting continents "Security personnel told journalists filming video, 'We received orders. It is not allowed to film anymore,' " Turkish news agency DHA reported Wednesday.
Amateur video posted on YouTube showed scores of passengers leaving a stopped train and walking down the long tube that has been constructed underneath the rushing waters of the Bosphorus Strait, effectively linking the European and Asian halves of Turkey's largest city.
Turkey's Marmaray project: An ambitious plan to link Europe and Asia
Because of an unexpectedly large volume of curious first-time passengers, the railway agency also said it had decided to skip one of the stops on the train's transcontinental route.
The Marmaray Tunnel is part of a $4.5 billion, 76-kilometer (47-mile) megaproject launched by the Turkish government in 2004.
Speaking at a ribbon-cutting ceremony attended by Japan's Prime Minister, Turkish Prime Minister Recep Tayyip Erdogan said the project "connects history and future, past and future; as well as connecting continents, Marmaray connects people, nations and countries."
The rail system, built by a Turkish-Japanese consortium, is expected to have a capacity of 1.5 million people a day, connecting the two continents in about four minutes. The 13.6-kilometer (8.5-mile) tunnel -- the deepest of its kind -- passes under the Bosphorus Strait, one of the busiest shipping arteries in the world.
The world's spectacular infrastructure projects
The financial capital of Istanbul, with a population of nearly 15 million people, is often snarled with traffic, with about 2 million residents making the crossing between continents on a daily basis.
Beyond the size of such an undertaking, digging for the Marmaray uncovered about 40,000 artifacts and helped archaeologists trace Istanbul's history back 8,500 years, 2,500 more than ever believed before.
However, the discoveries delayed the project for four years, which frustrated the Prime Minister who, analysts and businessmen say, wants to put a permanent imprint on Turkey's financial capital.
The project also had to account for Turkey's long history of violent earthquakes and the tunnel's position parallel to a major fault line. Transport minister Binali Yildirim has outlined the precautions, saying the tunnel allows movement and is designed to handle a quake of 9.0 magnitude.
Connecting continents amid earthquakes
The Turkish government has also begun construction of a third suspension bridge across the Bosphorus Strait. It also plans to build a third airport for Istanbul and dredge a canal to run parallel to the Bosphorus.
The massive government-backed development projects have become a politically polarizing issue in Turkey.
Anti-government protests erupted last summer after the government announced plans to bulldoze a park in central Istanbul and replace it with a shopping mall.
As government officials and crowds of supporters applauded the Marmaray tunnel's inauguration Tuesday, in other parts of Istanbul, riot police clashed with demonstrators protesting the Turkish government.
The world's spectacular infrastructure projects
CNN's John Defterios contributed to this report.
