Westminster Abbey is one of Britain’s most popular tourist attractions, but the vast majority of visitors have never seen its best feature: the view of the interior from the triforium, a space used as an attic in the upper levels of the Abbey. It was called "the finest view in Europe” by Sir John Betjeman, former poet laureate of Great Britain. That space is being remodeled into a museum, and in the process of cleaning it out, reports Maev Kennedy at The Guardian, researchers discovered 30,000 shards of stained glass from over the course of centuries of changes at the Abbey. Those shards have since been conserved and are being reconstituted into new displays for a recently built tower.

Kennedy reports that archaeologist Warwick Rodwell first noticed the shards of glass glittering among dust and dirt while sifting through deep cone-shaped pits in the Abbey's attics. “Once I saw the glass, the penny dropped,” he said. “I realized this was treasure, not rubbish, and we would have to go through every inch of it. The workmen thought I was mad.”

In fact, Rodwell and his team conducted a full-on archaeological dig, taking out every cubic inch of soot and dust in buckets and poring through the mess looking for glass and other artifacts. The glass fragments were sorted and taken to the stained glass studio at Cantebury Cathedral, which creates, restores and cleans stained glass from around Great Britain. There restorationists have photographed every fragment and tried to piece what they can together.

“There are puzzles upon puzzles upon puzzles,” Leonie Seliger, who is leading the project, tells Kennedy. “We have one piece of Victorian glass, all the rest is Medieval including thousands of pieces of flower-painted grisaille from windows which nobody knew had been in the abbey – the 19th-century antiquarians who crawled all over the place made no reference to it, so they must have already vanished without trace by then.”

Westminster Abbey, the gothic building in the heart of London, began as a Benedictine Abbey in the 10th century and has served as the place of coronation for kings and queens of the England and the United Kingdom since 1066. In 1245, Henry III began renovating the grand space into the Abbey seen today. It also serves as the resting place for 3,300 notables from the United Kingdom including kings, queens, politicians, scientists and writers, such as Charles Dickens and Rudyard Kipling, who rest in the Abbey's "Poet's Corner." While the Abbey had a previous museum, it closed in 2015 and will be replaced by the new space in the attic which will be called the Queen's Diamond Jubilee Galleries.

The glass is not the only awesome find made while cleaning out the triforium. John Bingham at The Telegraph reports that historians exploring the space have removed and catalogued thousands of artifacts while preparing for the museum construction. There were old oak doors, throne-like chairs, dozens of statues and lots of pieces of broken stone that had fallen off the Abbey over the centuries.

In another article, Kennedy reports that royal armor, a memorial to the author of “The Beggar’s Opera” and the world’s oldest-known stuffed parrot were also found. Many of the artifacts will be on display in the museum when it opens, scheduled for June, 2018.

While the Queen's Diamond Jubilee Gallery will highlight the history of the Abbey’s stained glass windows, other windows are still evolving. Many of the 16th-century stained glass windows in the Lady Chapel, which houses the tombs of Elizabeth I and Mary, Queen of Scots, were destroyed in World War II during the Blitz, and in recent years, Westminster Abbey has been replacing them with new art. In 2000, stained-glass artist Alan Younger contributed new windows and, in 2013, the chapel added more designed by Hughie O’Donoghue.

Editor's note, January 2, 2017: This story incorrectly reported that Jane Austen is buried in the Westminster Abbey's "Poet's Corner." In fact, the writer is buried in Winchester Cathedral in Hampshire. A small tablet was dedicated in her honor in the Poet's Corner in 1967. Additionally, this piece incorrectly referred to the Abbey as a cathedral. It is a "Royal Peculiar."