Game of Thrones is easily one of the biggest TV shows of all time, in more ways than one. It may arguably have one of the largest group of fans. But it's also easily the biggest show in terms of production scale, with the fantasy drama shooting in several different countries all at once. With Season 6 premiering in less than a month, debuting Sunday, April 24, series creator and showrunner D.B. Weiss told Entertainment Weekly that they had a unique challenge to face this season: A rockslide.

The rockslide happened at the show's Castle Black set, at Northern Ireland's Magheramorne Quarry. The production has built a practical and functional castle set that rests at the bottom of a rockface, which is dressed to look like an icy wall. The show films during what is typically the region's "extremely cold winter downpour," which doesn't show up on the show. In fact, several nights during the Battle of Castle Black scene were filmed during "heavy rainfall." As it turns out, though, the heavy rain has altered the rockface's "seismic profile," which lead to the life-threatening rockslide. Here's what D.B. Weiss had to say.

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"Once people saw the small pebbles start to come down that turned into slightly larger pebbles, everybody made the group decision to immediately step away from the set."

Actor Owen Teale, who plays Ser Alliser Thorne, described the event as "A piece of rock the size of a London townhouse" falling to the Earth. No cast or crew members were injured, but the event wreaked havoc on the show's meticulous shooting schedule, which is mapped out months in advance. Executive producer Bernadette Caulfield and producer Chris Newman are responsible for mapping out the show's entire shooting schedule, which D.B. Weiss claims is the hardest job on television. Here's what the showrunner had to say about how the rockslide threw a monkey wrench into their schedule.

"Bernie and Chris already have hardest scheduling job in the film and TV industry, and they had this thrown into the works too, which caused them to drastically reschedule the whole season on the fly. But they did it, and we got everything we needed in that quarry after it was seismically shored up and netted and proper protection measures were taken. It actually worked out for the best - some of the stuff we were shooting in that location benefited from the additional prep time the rockslide gave us."

A new trailer released earlier this month features a number of action-packed battle sequences, and both Game of Thrones series creators D.B. Weiss and David Benioff recently teased this season will have the biggest battle in TV history. Series star Liam Cunningham, who plays Davos Seaworth, also recently teased that Game of Thrones Season 6 will feature a lot of deaths, many of which may be surprising. What do you think about these new Game of Thrones details?