In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Let me give you an example: Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
The answer to this example can be: Who believes Fagin's gang make wallets and handkerchiefs?.
Here is why: This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

OK. solve this:
Passage: Lennon first met Yoko Ono on 9 November 1966 at the Indica Gallery in London, where Ono was preparing her conceptual art exhibit. They were introduced by gallery owner John Dunbar. Lennon was intrigued by Ono's "Hammer A Nail": patrons hammered a nail into a wooden board, creating the art piece. Although the exhibition had not yet begun, Lennon wanted to hammer a nail into the clean board, but Ono stopped him. Dunbar asked her, "Don't you know who this is? He's a millionaire! He might buy it." Ono had supposedly not heard of the Beatles, but relented on condition that Lennon pay her five shillings, to which Lennon replied, "I'll give you an imaginary five shillings and hammer an imaginary nail in." Ono subsequently related that Lennon had taken a bite out of the apple on display in her work Apple, much to her fury.Ono began to telephone and visit Lennon at his home. When Cynthia asked him for an explanation, Lennon explained that Ono was only trying to obtain money for her "avant-garde bullshit". While his wife was on holiday in Greece in May 1968, Lennon invited Ono to visit. They spent the night recording what would become the Two Virgins album, after which, he said, they "made love at dawn". When Lennon's wife returned home she found Ono wearing her bathrobe and drinking tea with Lennon who simply said, "Oh, hi." Ono became pregnant in 1968 and miscarried a male child on 21 November 1968, a few weeks after Lennon's divorce from Cynthia was granted.Two years before the Beatles disbanded, Lennon and Ono began public protests against the Vietnam War. They were married in Gibraltar on 20 March 1969, and spent their honeymoon at the Hilton Amsterdam, campaigning with a week-long Bed-In for Peace. They planned another Bed-In in the United States but were denied entry, so they held one instead at the Queen Elizabeth Hotel in Montreal, where they recorded "Give Peace a Chance". They often combined advocacy with performance art, as in their "Bagism", first introduced during a Vienna press conference. Lennon detailed this period in the Beatles song "The Ballad of John and Yoko". Lennon changed his name by deed poll on 22 April 1969, adding "Ono" as a middle name. The brief ceremony took place on the roof of the Apple Corps building, where the Beatles had performed their rooftop concert three months earlier. Although he used the name John Ono Lennon thereafter, official documents referred to him as John Winston Ono Lennon, since he was not permitted to revoke a name given at birth. The couple settled at Tittenhurst Park at Sunninghill in Berkshire. After Ono was injured in a car accident, Lennon arranged for a king-size bed to be brought to the recording studio as he worked on the Beatles' last album, Abbey Road.Ono and Lennon moved to New York, to a flat on Bank Street, Greenwich Village. Looking for somewhere with better security, they relocated in 1973 to the more secure Dakota overlooking Central Park at 1 West 72nd Street.
Answer:
Where were John Lennon and Yoko married?