Question: Where was the capital before the location where Bach Main Airfield is located?

full_context: Document 1: Geography of Vietnam: Vietnam is located on the eastern margin of the Indochinese peninsula and occupies about 331,211.6 square kilometers, of which about 25% was under cultivation in 1987. It borders the Gulf of Thailand, Gulf of Tonkin, and Pacific Sea, alongside China, Laos, and Cambodia. The S - shaped country has a north - to - south distance of 1,650 kilometers and is about 50 kilometers wide at the narrowest point. With a coastline of 3,260 kilometers, excluding islands, Vietnam claims 12 nautical miles (22.2 km; 13.8 mi) as the limit of its territorial waters, an additional 12 nautical miles (22.2 km; 13.8 mi) as a contiguous customs and security zone, and 200 nautical miles (370.4 km; 230.2 mi) as an exclusive economic zone.
Document 2: 22 Gia Long Street: 22 Gia Long Street, now 22 Lý Tự Trọng Street, is an apartment building in Ho Chi Minh City, then called Saigon, that became an icon of the Fall of Saigon when chosen as an assembly point for Operation Frequent Wind in 1975. A Dutch photographer, Hubert van Es, working for UPI, took a photograph that captured the chaotic final days of the Vietnam War, which many people believed showed desperate Americans crowding on to the roof of the United States Embassy to board a helicopter. The building in fact was an apartment building that housed employees of the United States Agency for International Development (USAID), with its top floor reserved for the Central Intelligence Agency's deputy chief of station.
Document 3: Ho Chi Minh City: Ho Chi Minh City Thành phố Hồ Chí Minh Saigon or Sài Gòn Municipality Thành phố trực thuộc trung ương Clockwise, from left to right: Bến Thành Market, Ho Chi Minh City Hall, District 1 view from Saigon river, Municipal Theatre, Notre - Dame Cathedral Basilica of Saigon, Independence Palace Seal Nickname (s): Pearl of the Far East Location in Vietnam and Southern Vietnam Coordinates: 10 ° 46 ′ 36.8 ''N 106 ° 42 ′ 02.9'' E ﻿ / ﻿ 10.776889 ° N 106.700806 ° E ﻿ / 10.776889; 106.700806 Coordinates: 10 ° 46 ′ 36.8 ''N 106 ° 42 ′ 02.9'' E ﻿ / ﻿ 10.776889 ° N 106.700806 ° E ﻿ / 10.776889; 106.700806 Country Vietnam Central district District 1 Founded as Gia Định 1698 Renamed to Ho Chi Minh City 1976 Founded by Nguyễn Hữu Cảnh Divisions 19 Urban districts, 5 Suburban districts Government Type Special - class Secretary of Communist Party Nguyễn Thiện Nhân Chairman of People's Committee Nguyễn Thành Phong Chairman of People's Council Nguyễn Thị Quyết Tâm Area Total 2,096.56 km (809.23 sq mi) Elevation 19 m (63 ft) Population (2016) Total 8,426,100 Rank 1st Density 4,000 / km (10,000 / sq mi) GDP (PPP) (2015 estimate) Total US $127.8 billion Per capita US $15,977 GRDP (nominal) (2016) Total US $45.73 billion Per capita US $5,428 Time zone ICT (UTC + 07: 00) Area codes 8 (until 16 Jul 2017) 28 (from 17 Jun 2017) Website hochiminhcity.gov.vn
Document 4: France–Vietnam relations: French -- Vietnamese relations started as early as the 17th century with the mission of the Jesuit father Alexandre de Rhodes. Various traders would visit Vietnam during the 18th century, until the major involvement of French forces under Pigneau de Béhaine from 1787 to 1789 helped establish the Nguyễn Dynasty. France was heavily involved in Vietnam in the 19th century under the pretext of protecting the work of Catholic missionaries in the country. France progressively carved for itself a huge colony, which would form French Indochina in 1887. France continued to rule Vietnam as a colony until France's defeat in the First Indochina War and the proclamation of Vietnam's independence in 1954.
Document 5: History of Vietnam: After Quang Trung's death, the Tây Sơn dynasty became unstable as the remaining brothers fought against each other and against the people who were loyal to Nguyễn Huệ's infant son. Nguyễn Ánh sailed north in 1799, capturing Tây Sơn's stronghold Qui Nhơn. In 1801, his force took Phú Xuân, the Tây Sơn capital. Nguyễn Ánh finally won the war in 1802, when he sieged Thăng Long (Hanoi) and executed Nguyễn Huệ's son, Nguyễn Quang Toản, along with many Tây Sơn generals and officials. Nguyễn Ánh ascended the throne and called himself Emperor Gia Long. Gia is for Gia Định, the old name of Saigon; Long is for Thăng Long, the old name of Hanoi. Hence Gia Long implied the unification of the country. The Nguyễn dynasty lasted until Bảo Đại's abdication in 1945. As China for centuries had referred to Đại Việt as Annam, Gia Long asked the Manchu Qing emperor to rename the country, from Annam to Nam Việt. To prevent any confusion of Gia Long's kingdom with Triệu Đà's ancient kingdom, the Manchu emperor reversed the order of the two words to Việt Nam. The name Vietnam is thus known to be used since Emperor Gia Long's reign. Recently historians have found that this name had existed in older books in which Vietnamese referred to their country as Vietnam.
Document 6: Paris: The Pagode de Vincennes Buddhist temple, near Lake Daumesnil in the Bois de Vincennes, is the former Cameroon pavilion from the 1931 Paris Colonial Exposition. It hosts several different schools of Buddhism, and does not have a single leader. It shelters the biggest Buddha statue in Europe, more than nine metres high. There are two other small temples located in the Asian community in the 13th arrondissement. A Hindu temple, dedicated to Ganesh, on Rue Pajol in the 18th arrondissement, opened in 1985.
Document 7: French Indochina: A grouping of the three Vietnamese regions of Tonkin (north), Annam (centre), and Cochinchina (south) with Cambodia was formed in 1887. Laos was added in 1893 and the leased Chinese territory of Guangzhouwan in 1898. The capital was moved from Saigon (in Cochinchina) to Hanoi (Tonkin) in 1902 and again to Da Lat (Annam) in 1939. In 1945 it was moved back to Hanoi.
Document 8: Mỹ Sơn: In 1937, French scholars began to restore the temples at Mỹ Sơn. In 1937 and 1938, the main temple known as "A1" and the smaller temples surrounding it were restored. Other major temples were restored between 1939 and 1943. However, many historical buildings were destroyed during the Vietnam War. United States B52 aircraft carpet-bombed the region in August 1969. The surrounding area is still rendered dangerous through the presence of unexploded land mines.
Document 9: Battle of Dien Bien Phu: Date 13 March -- 7 May 1954 (1 month, 3 weeks and 3 days) Location 21 ° 23 ′ 13 ''N 103 ° 0 ′ 56'' E ﻿ / ﻿ 21.38694 ° N 103.01556 ° E ﻿ / 21.38694; 103.01556 Coordinates: 21 ° 23 ′ 13 ''N 103 ° 0 ′ 56'' E ﻿ / ﻿ 21.38694 ° N 103.01556 ° E ﻿ / 21.38694; 103.01556 Vicinity of Điện Biên Phủ, Vietnam Result Decisive Viet Minh victory Termination of French involvement in Indochina Signing of Geneva Conference (1954) End of the First Indochina War Territorial changes Vietnam is temporarily divided at the 17th Parallel
Document 10: Museum of Vietnamese History: The Museum of Vietnamese History is located at 2 Nguyen Binh Khiem Street, Ben Nghe Ward, District 1, in Ho Chi Minh City, Vietnam. Formerly known as the Musée Blanchard de la Brosse, built by Auguste Delaval in 1926, and The National Museum of Viet Nam in Sai Gon, it received its current name in 1979. It is a museum showcasing Vietnam's history with exhibits from all periods. It should not be confused with the National Museum of Vietnamese History in Hanoi. The topics covered by the exhibits include the following:
Document 11: North Vietnam: After about 300 years of partition by feudal dynasties, Vietnam was again under one single authority in 1802 when Gia Long founded the Nguyễn dynasty, but the country became a French protectorate after 1883 and under Japanese occupation after 1940 during World War II. Soon after Japan surrendered on September 2, 1945, the Việt Minh in the August Revolution entered Hanoi, and the Democratic Republic of Vietnam was proclaimed on September 2, 1945: a government for the entire country, replacing the Nguyễn dynasty. Hồ Chí Minh became leader of the Democratic Republic of Vietnam. U.S. President Franklin Roosevelt had spoken against French rule in Indochina, and U.S.A. was supportive of the Viet Minh at this time.
Document 12: Auguste Henri Vildieu: Auguste Henri Vildieu was the French architectural adjutant in Hanoi while that city was an administrative center for the French colony of Indochina. Vildieu constructed several grand European-style buildings for the colonial government, including:
Document 13: Bach Mai Airfield: Bach Mai Airfield () is a disused military airport in Thanh Xuan District, Hanoi, Vietnam, located along modern-day Le Trong Tan street. It was constructed by the French in 1917 and used by French forces until 1954; along with Gia Lam Airbase, it was one of the major logistics bases supporting French operations at Dien Bien Phu. After 1954, it was used by the Vietnamese People's Air Force and served as their air defense command and control center during the Second Indochina War, playing a part in the Cambodian–Vietnamese War as well. It is now the site of the Vietnam People's Air Force Museum, where a number of period military aircraft are on display.
Document 14: Patuxai: Patuxai (Lao: ປະຕູໄຊ, literally meaning Victory Gate or Gate of Triumph, formerly the Anousavary or Anosavari Monument, known by the French as Monument Aux Morts) is a war monument in the centre of Vientiane, Laos, built between 1957 and 1968. The Patuxai was dedicated to those who fought in the struggle for independence from France. In romanising the name from the Laotian language, it is variously transliterated as Patuxai, Patuxay, Patousai and Patusai. It is also called Patuxai Arch or the Arc de Triomphe of Vientiane as it resembles the Arc de Triomphe in Paris. However, it is typically Laotian in design, decorated with mythological creatures such as the kinnari (half-female, half-bird).
Document 15: Roye-Amy Airfield: Originally a 1930s airport which was seized by the Germans during the Battle of France, it was used by the Luftwaffe, then by the United States Army Air Forces during World War II. After the war, the site was abandoned and is now agricultural fields.
ground_truth: Saigon
sub_queries: Bach Mai Airfield >> place served by transport hub Answer: Hanoi
Where was the capital before Hanoi ? Answer: Saigon