Giant's Causeway cases the horizontal fracture has resulted in a bottom face that is convex while the upper face of the lower segment is concave, producing what are called "ball and socket" joints. The size of the columns is primarily determined by the speed at which lava from a volcanic eruption cools. The extensive fracture network produced the distinctive columns seen today. The basalts were originally part of a great volcanic plateau called the Thulean Plateau which formed during the Paleocene. According to legend, the columns are the remains of a causeway built by a giant. The story goes that the Irish
Secret of the Cave events and deeds begin to occur and rumors of ghosts sweep the village. All these things are pointing to something mysterious that is going on in a nearby cave. Roy sets out to disprove the rumor and decides to explore the cave with his new, teenage local friends Oscar (Gareth O'Connor) and Abbey (Niamh Finn). Roy faces his fears and discovers the secret of the cave. The film is based on the 1920 children's book of the same name by Arthur S. Maxwell (also known as "Uncle Arthur"). The book has sold more than 142,000 copies worldwide in English, Spanish,