Task: Question Answering
Input (English): Passage: Nigel Reuben Rook Williams (15 July 1944 – 21 April 1992) was an English conservator and expert on the restoration of ceramics and glass. From 1961 until his death he worked at the British Museum, where he became the Chief Conservator of Ceramics and Glass in 1983. There his work included the successful restorations of the Sutton Hoo helmet and the Portland Vase.
Joining as an assistant at age 16, Williams spent his entire career, and most of his life, at the British Museum. He was one of the first people to study conservation, not yet recognised as a profession, and from an early age was given responsibility over high-profile objects. In the 1960s he assisted with the re-excavation of the Sutton Hoo ship-burial, and in his early- to mid-twenties he conserved many of the objects found therein: most notably the Sutton Hoo helmet, which occupied a year of his time. He likewise reconstructed other objects from the find, including the shield, drinking horns, and maplewood bottles.
The "abiding passion of his life" was ceramics, and the 1970s and 1980s gave Williams ample opportunities in that field. After nearly 31,000 fragments of shattered Greek vases were found in 1974 amidst the wreck of HMS Colossus, Williams set to work piecing them together. The process was televised, and turned him into a television personality. A decade later, in 1988 and 1989, Williams's crowning achievement came when he took to pieces the Portland Vase, one of the most famous glass objects in the world, and put it back together. The reconstruction was again televised for a BBC programme, and as with the Sutton Hoo helmet, took nearly a year to complete.
Williams died at age 47 of a heart attack while in Aqaba, Jordan, where he was working on a British Museum excavation. The Ceramics & Glass group of the Institute of Conservation awards a biennial prize in his honour, recognising his significant contributions in the field of conservation. 
Question: What was the most famous glass object in the world that Williams put back together?
Output (English): the Portland Vase.