Piping pseudokarst. The 2010 Guatemala City sinkhole formed suddenly in May of that year; torrential rains from Tropical Storm Agatha and a bad drainage system were blamed for its creation. It swallowed a three-story building and a house; it measured approximately 20 m (66 ft) wide and 30 m (98 ft) deep.
âFour legs good, two legs bad.â This phrase, which occurs in Chapter III, constitutes Snowballâs condensation of the Seven Commandments of Animalism, which themselves serve as abridgments of Old Majorâs stirring speech on the need for animal unity in the face of human oppression.
Scientists claim that walking on two legs was one of the keys to humans' development from ancient ape-like ancestors. Walking on two legs saved energy and allowed the arms to be used for activities like hunting, crafting simple tools and interacting with objects. Charles Darwin proposed long ago that having two limbs free to use tools constituted a key element of advanced intelligence [source: National Geographic].