Answer the following question: Information:  - Tuti Island (also spelled Tutti Island) is an island in Sudan where the White Nile and Blue Nile merge to form the main Nile. It is surrounded by the "Three Towns": Khartoum (the capital of Sudan), Omdurman (the largest city in Sudan), and Khartoum North (also known as Bahri, a large industrial center). Despite this, Tuti is home to only one small village (founded in the late 15th century), with grassland being the main makeup of the island. In the past the only approach to Tuti Island was via several ferries that cross the river every so often, but now the Tuti Bridge, a modern suspension bridge, has been completed and can be used instead. Tuti Island is mainly agricultural and where Khartoum gets most of its supply of fruits and vegetables and therefore, you can find many farms situated all around the island, many of them still using manual methods of farming. You will find acres of green fields and lime groves.  - The Tuti - Kartoum Bridge is a modern suspension bridge linking between Tuti Island and the City of Khartoum that was completed in February 2008 . In the past the only approach to Tuti Island was via ferries but thanks to the Tuti - Khartoum Bridge , easy access to the island is possible . The Tuti Bridge in Khartoum is considered to be the first suspension bridge to be constructed in Sudan and one of the first constructed in Africa . The concept design of the bridge was proposed by Alfatih Ahmed , with the final working design by A&A Company Its construction depended on new bridge technology , enabling the erection to be carried out using local expertise & equipment . The Tuti - Kartoum Bridge is the first among a series of bridges that will connect the cities of Khartoum , Omdurman and Bahri ( North Khartoum ) , and will help to alleviate traffic throughout the cities . The development has immediately commercialized the previously isolated Tuti Island .  - Lake Victoria (' in Luo; ' in Luganda; "" in Kinyarwanda and some Bantu languages) is one of the African Great Lakes. The lake was named after Queen Victoria by the explorer John Hanning Speke, the first Briton to document it. Speke accomplished this in 1858, while on an expedition with Richard Francis Burton to locate the source of the Nile River.  - Omdurman (standard "Umm Durmn") is the largest city in Sudan and Khartoum State, lying on the western banks of the River Nile, opposite the capital, Khartoum. Omdurman has a population of 2,395,159 (2008) and is the national centre of commerce. With Khartoum and Khartoum North or Bahri, it forms the cultural and industrial heart of the nation.  - The White Nile ("") is a river of Africa, one of the two main tributaries of the Nile, the other being the Blue Nile.  - Khartoum is the capital and second largest city of Sudan and Khartoum state. It is located at the confluence of the White Nile, flowing north from Lake Victoria, and the Blue Nile, flowing west from Ethiopia. The location where the two Niles meet is known as ""al-Mogran"" , meaning the confluence. The main Nile continues to flow north towards Egypt and the Mediterranean Sea.  - The Nile ( "en-Nl",  "an-Nl" "P(h)iaro"; Ancient Egyptian: "'p" and "Iteru"; Biblical Hebrew: , "Ha-Ye'or") is a major north-flowing river in northeastern Africa. It is generally regarded as the longest river in the world, however other conflicting sources cite a 2007 study that gave the title to the Amazon River in South America. The Nile, which is 6,853 km (4,258 miles) long, is an "international" river as its water resources are shared by eleven countries, namely, Tanzania, Uganda, Rwanda, Burundi, Congo-Kinshasa, Kenya, Ethiopia, Eritrea, South Sudan, Sudan and Egypt. In particular, the Nile is the primary water source of Egypt and Sudan.  - Khartoum North or Bahri ("al-Kharm Bar") is the third-largest city in the Republic of Sudan. It is located on the east bank of the Blue Nile near its confluence with the White and bridges connect it with Khartoum to its south and Omdurman to its west.  - In geography, a confluence is the meeting of two or more bodies of water. Also known as a "conflux", it refers either to the point where a tributary joins a larger river, (main stem), or where two streams meet to become the source of a river of a new name, such as the confluence of the Monongahela and Allegheny rivers in Pittsburgh, Pennsylvania creating the Ohio River.  - Sudan ("as-Sdn", ), also known as North Sudan and officially the Republic of the Sudan ("Jumhriyyat as-Sdn"), is a country in Northern Africa. It is bordered by Egypt to the north, the Red Sea, Eritrea, and Ethiopia to the east, South Sudan to the south, the Central African Republic to the southwest, Chad to the west and Libya to the northwest. It is the third largest country in Africa. The River Nile divides the country into eastern and western halves. Before the Sudanese Civil War, South Sudan was part of Sudan but broke away in 2011. Its predominant religion is Islam.  - The Blue Nile (transliterated: Abbay but pronounced "Abbai", "") is a river originating at Lake Tana in Ethiopia. With the White Nile, the river becomes one of the two major tributaries of the Nile. The upper course of the river is called the Abbay in Ethiopia, where many regard it as holy. Some Ethiopians have long identified the Blue Nile as the River Gihon mentioned as flowing out of the Garden of Eden in Genesis 2 and "encircling the entire land of Cush".    What entity does 'tuti bridge' has the relation 'crosses' with?
Answer:
blue nile