The Silent House (Teaser trailer HD English)
via youtube.com
promoted as 'the first horror film in one single continuous shot," filmed in Uruguay. And though the translation is a bit off, the trailer seems to suggest it was shot in some notable way - the english is shot on a 'photo camera' (???) It's likely not the first though as Robert Archer Lynn's Deadbox (2007) also sold itself as one 105 minute take.