text: The traditional name of the circuit ( literally , `` between lakes '' ) comes from the fact that it was built in a region between two large artificial lakes , Guarapiranga and Billings , which were built in the early 20th century to supply the city with water and electric power .
simplified: It comes from the fact that it was built between two large artificial lakes , Guarapiranga and Billings . They were built in the early 20th century to supply the city with water and electric power .