premise: The Roque Cinchado is a rock formation, regarded as emblematic of the island of Tenerife (Canary Islands, Spain). It lies within the Teide National Park (a World Heritage Site) in the municipality of La Orotava, near the volcano of the same name, in the heart of the island. The Roque Cinchado is one of the largest in the world by altitude, for the entire park totals more than 2000 metres.
hypothesis: The Roque Cinchado is the largest rock formation in the world. 
reason: It is one of the largest in altitude, but no mention of actual size