Question: The mother of Julian Lennon unveiled what monument in Liverpool, England? 

full_context: Document 1: Maureen Starkey Tigrett: Maureen "Mo" Starkey Tigrett (born Mary Cox; 4 August 1946 – 30 December 1994) was a hairdresser from Liverpool, England, best known as the first wife of Ringo Starr, the Beatles' drummer. When she was a trainee hairdresser in Liverpool, she met Starr at The Cavern Club, where the Beatles were playing. Starr proposed marriage at the Ad-Lib Club in London, on 20 January 1965. They married at the Caxton Hall Register Office, London, in 1965, and divorced in 1975.
Document 2: Murder of John Lennon: John Lennon was an English musician who gained worldwide fame as one of the members of the Beatles, for his subsequent solo career, and for his political activism and pacifism. On Monday, December 8, 1980, Lennon was shot dead by Mark David Chapman in the archway of the Dakota, his residence in New York City. Lennon had just returned from Record Plant Studio with his wife, Yoko Ono.
Document 3: Cynthia Cozette Lee: Cynthia Cozette Lee, also known as Cynthia Cozette or Nazik Cynthia Cozette (born October 19, 1953, in Pittsburgh, Pennsylvania) is a contemporary African-American classical music composer and librettist. Cozette was the first African-American woman to graduate from the University of Pennsylvania with a Masters of Arts Degree in music composition . Cozette was also the first African-American woman graduate of the University of Pennsylvania to be instructed in music composition by the American composers, George Crumb and George Rochberg.
Document 4: Julian Lennon: John Charles Julian Lennon (born 8 April 1963) is an English musician and photographer. Lennon is the child of John Lennon and his first wife, Cynthia.
Document 5: Manorhaus, Ruthin: Manorhaus is currently a boutique restaurant with rooms and is also an art gallery. It was owned by John Lennon's first wife, Cynthia Lennon, and their son, Julian Lennon, attended Ruthin School. Manorhaus has 8 rooms, each decorated with a different theme and interior design by local artists. It also has a gym, sauna, steam room and also a well-stocked library available to guests.
Document 6: John Lennon Peace Monument: The John Lennon Peace Monument, also known as the European Peace Monument, is a peace monument entitled Peace & Harmony in Liverpool, England, dedicated to the memory of John Lennon. "Peace & Harmony" was unveiled by Julian and Cynthia Lennon at a ceremony in Chavasse Park, Liverpool, on Saturday 9 October 2010 to celebrate what would have been John Lennon's 70th birthday. The monument is now on the waterfront adjacent to ACC Liverpool at Kings Dock.
Document 7: Ivan Vaughan: Ivan Vaughan (18 June 1942 – 16 August 1993) was a boyhood friend of John Lennon, and later schoolmate of Paul McCartney at the Liverpool Institute, both commencing school there in September 1953. He was born on the same day as McCartney in Liverpool. He played bass part-time in Lennon's first band, The Quarrymen, and was responsible for introducing Lennon to McCartney at a community event (the Woolton village fête) on 6 July 1957, where The Quarrymen were performing. McCartney impressed Lennon, who invited McCartney to join the band, which he did a day later. This led to the formation of Lennon and McCartney's songwriting partnership, and later of The Beatles.
Document 8: Imagine Peace Tower: The Imagine Peace Tower (Icelandic: "Friðarsúlan" , meaning "the peace column") is a memorial to John Lennon from his widow, Yoko Ono, located on Viðey Island in Kollafjörður Bay near Reykjavík, Iceland. It consists of a tall tower of light, projected from a white stone monument that has the words "Imagine Peace" carved into it in 24 languages. These words, and the name of the tower, are a reference to Lennon's campaign for peace, and his song "Imagine".
Document 9: Unfinished Music No. 1: Two Virgins: Unfinished Music No. 1: Two Virgins is the first of three experimental albums released by John Lennon and Yoko Ono on Apple Records. It was the result of an all-night session of musical experimentation with Yoko in John's home studio at Kenwood, while his wife, Cynthia Lennon, was on holiday in Greece. Their debut recording is known not only for its avant-garde content, but also for its cover which features the couple naked: This made the album controversial to both the public and the parent record company EMI, which refused to distribute it. In an attempt to avoid controversy, the LP record was sold in a brown paper bag, and distributed by Track and Tetragrammaton in the United Kingdom and the United States respectively. "Two Virgins", while failing to chart in the UK, reached number 124 in the US. The album was followed six months later by "".
Document 10: Yellow Submarine (sculpture): The Yellow Submarine in Liverpool is a large model representation of the submarine featured in the animated film "Yellow Submarine", inspired by the song of the same name on the Beatles album "Revolver". It was built by a group of about 80 apprentices from Cammell Laird's shipyard, designed in part by Mr L Pinch, a draughtsman at the yard, for exhibition at the International Garden Festival in Liverpool in 1984. The Submarine was in a garden themed around the Beatles, one of 60 such themed gardens, and was highly popular. The garden took the form of an apple-shaped labyrinth, containing symbolic references to the group, and included a bronze statue of John Lennon, which now stands at Liverpool John Lennon Airport.
Document 11: Liverpool 08 Collection: The Liverpool 08 Collection was the Public art collection exhibited by Liverpool John Lennon Airport in conjunction with the Liverpool Culture Company for the duration of 2008, the year when Liverpool was the European Capital of Culture. Exhibits were launched before and during the year by various celebreties including Yoko Ono and Phil Redmond and much of the exhibition remains in place today. As well as the iconic sculptures, The Yellow Submarine (sculpture) and the John Lennon Statue, the different pieces of artwork situated around the public areas of the terminal included; two rare suits worn by John Lennon, photographs by Harry Goodwin and Paul Saltzman, mosaics from Debbie Ryan, graphic designs by John McFaul, a film by Nick Jordan, a performance of Brian Eno's 'Music for Airports' and artwork from 50 schoolchildren at St Ambrose Primary School in Speke
Document 12: Lennon Wall (Hong Kong): Lennon Wall refers to the artistic form of expressions in the protest. Lennon Wall Hong Kong literally refers to the democratic mosaic wall created during the Umbrella Movement, located at Central Government Complex, Harcourt Road, Admiralty, which is one of the main landmarks in the occupation area of Admiralty and one of the major arts of the Umbrella Movement as collective artistic works demanding democracy in the election of the territory’s top leader.
Document 13: Cynthia Lennon: Cynthia Lennon (née Powell; 10 September 1939 – 1 April 2015) was the first wife of English musician John Lennon and mother of Julian Lennon. She grew up in the middle-class section of Hoylake, on the Wirral Peninsula in North West England. At the age of 12, she was accepted into the Junior Art School, and was later enrolled in the Liverpool College of Art. John Lennon also attended the college; a meeting with Powell in a calligraphy class led to their relationship.
Document 14: John Lennon Museum: John Lennon Museum (ジョン・レノン・ミュージアム , Jon Renon Myūjiamu ) was a museum located inside the Saitama Super Arena in Chūō-ku, Saitama, Saitama Prefecture, Japan. It was established to preserve knowledge of John Lennon's life and musical career. It displayed Lennon's widow Yoko Ono's collection of his memorabilia as well as other displays. The museum opened on October 9, 2000, the 60th anniversary of Lennon’s birth, and closed on September 30, 2010, when its exhibit contract with Yoko Ono expired. A tour of the museum began with a welcoming message and short film narrated by Yoko Ono (in Japanese with English headphones available), and ended at an avant-garde styled "reflection room" full of chairs facing a slide show of moving words and images. After this room there was a gift shop with John Lennon memorabilia available.
Document 15: Strawberry Fields (memorial): Strawberry Fields is a 2.5-acre (1.0 ha) landscaped section in New York City's Central Park, designed by the landscape architect Bruce Kelly, that is dedicated to the memory of former Beatle John Lennon. It is named after the Beatles' song "Strawberry Fields Forever" written by Lennon. The song is itself named for the former Strawberry Field children's home in Liverpool, England, located near Lennon's childhood home.
ground_truth: Peace & Harmony