Question:
Maurice Robert "Mike" Gravel (; born May 13, 1930) is an American politician who was a Democratic United States Senator from Alaska from 1969 to 1981 and a candidate in the 2008 U.S. presidential election. Born and raised in Springfield, Massachusetts, by French-Canadian immigrant parents, Gravel served in the U.S. Army in West Germany, and he later graduated from the Columbia University School of General Studies. He moved to Alaska in the late 1950s, becoming a real estate developer and entering politics. He served in the Alaska House of Representatives from 1963 to 1966 and also became Speaker of the Alaska House.
In the late 1960s and early 1970s the U.S. Department of Defense was in the process of performing tests for the nuclear warhead for the Spartan anti-ballistic missile. Two tests, the "Milrow" and "Cannikin" tests, were planned, involving the detonation of nuclear bombs under Amchitka Island in Alaska. The Milrow test would be a one megaton calibration exercise for the second, and larger five megaton, Cannikin test, which would measure the effectiveness of the warhead. Gravel opposed the tests in Congress. Before the Milrow test took place in October 1969, he wrote that there were significant risks of earthquakes and other adverse consequences, and called for an independent national commission on nuclear and seismic safety to be created; he then made a personal appeal to President Nixon to stop the test.  After Milrow was conducted, there was continued pressure on the part of environmental groups against going forward with the larger Cannikin test, while the Federation of American Scientists claimed that the warhead being tested was already obsolete. In May 1971, Gravel sent a letter to U.S. Atomic Energy Commission hearings held in Anchorage, in which he said the risk of the test was not worth taking. Eventually a group not involving Gravel took the case to the U.S. Supreme Court, which declined to issue an injunction against it, and the Cannikin test took place as scheduled in November 1971. Gravel had failed to stop the tests (notwithstanding his later claims during his 2008 presidential campaign).  Nuclear power was considered an environmentally clean alternative for the commercial generation of electricity and was part of a popular national policy for the peaceful use of atomic energy in the 1950s and 1960s. Gravel publicly opposed this policy; besides the dangers of nuclear testing, he was a vocal critic of the Atomic Energy Commission, which oversaw American nuclear efforts, and of the powerful United States Congress Joint Committee on Atomic Energy, which had a stranglehold on nuclear policy and which Gravel tried to circumvent. In 1971, Gravel sponsored a bill to impose a moratorium on nuclear power plant construction and to make power utilities liable for any nuclear accidents; in 1975, he was still proposing similar moratoriums. By 1974, Gravel was allied with Ralph Nader's organization in opposing nuclear power.  Six months before U.S. Secretary of State Henry Kissinger's secret mission to the People's Republic of China (P.R.C.) in July 1971, Gravel introduced legislation to recognize and normalize relations with China, including a proposal for unity talks between the P.R.C. and the Republic of China (Taiwan) regarding the Chinese seat on the U.N. Security Council. Gravel reiterated his position in favor of recognition, with four other senators in agreement, during Senate hearings in June 1971.
Answer this question using a quote from the text above:

Why did he oppose nuclear testing?

Answer:
besides the dangers of nuclear testing,


Question:
Roger Keith "Syd" Barrett (6 January 1946 - 7 July 2006) was an English singer, songwriter, musician, composer, and painter. Best known as a founder member of the band Pink Floyd, Barrett was the lead singer, guitarist and principal songwriter in its early years and is credited with naming the band. Barrett was excluded from Pink Floyd in April 1968 after David Gilmour took over as their new guitarist, and was briefly hospitalised amid speculation of mental illness. Barrett was musically active for less than ten years.
While Pink Floyd began by playing cover versions of American R&B songs, by 1966 they had carved out their own style of improvised rock and roll, which drew as much from improvised jazz. After Bob Klose departed from the band, the band's direction changed. However, the change was not instantaneous, with more improvising on the guitars and keyboards. Mason reflected, "It always felt to me that most of the ideas were emanating from Syd at the time."  At this time, Barrett's reading reputedly included: Grimm's Fairy Tales, Tolkien's The Hobbit and Lord of the Rings, Carlos Castaneda's The Teachings of Don Juan, and The I-Ching. During this period, Barrett wrote most of the songs for Pink Floyd's first album, and also songs that would later appear on his solo albums. In 1966, a new rock concert venue, the UFO (pronounced as "you-foe"), opened in London and quickly became a haven for British psychedelic music. Pink Floyd, the house band, was its most popular attraction and after making appearances at the rival Roundhouse, became the most popular musical group of the "London Underground" psychedelic music scene.  By the end of 1966, Pink Floyd had gained a reliable management team in Andrew King and Peter Jenner. Towards the end of October 1966, Pink Floyd, with King and Jenner, set up Blackhill Enterprises, to manage the group's finances. Blackhill was staffed by lodgers Jenner found in his Edbrooke Road house, and among others, Barrett's flatmate, Peter Wynne Wilson (who became road manager, however, since he had more experience in lighting, he was also lighting assistant). King and Jenner wanted to prepare some demo recordings for a possible record deal, so at the end of October, they booked a session at Thompson Private Recording Studio, in Hemel Hempstead. King said of the demos: "That was the first time I realised they were going to write all their own material, Syd just turned into a songwriter, it seemed like overnight."  King and Jenner befriended American expatriate Joe Boyd, the promoter of the UFO Club, who was making a name for himself as one of the more important entrepreneurs on the British music scene. The newly hired booking agent, Bryan Morrison, and Boyd had proposed sending in better quality recordings. From Morrison's agency the band played a gig outside London for the first time. In November, the band performed the first (of many) strangely named concerts: Philadelic Music for Simian Hominids, a multimedia event arranged by the group's former landlord, Mike Leonard, at Hornsey College of Art. They performed at the Free School for the following two weeks, before performing at the Psychodelphia Versus Ian Smith event at the Roundhouse in December, arranged by the Majority Rule for Rhodesia Campaign, and an Oxfam benefit at the Albert Hall (the band's biggest venue up to this point).
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What did he do in London Underground?

Answer:
became the most popular musical group of the "London Underground" psychedelic music scene.