Construction on the Green Bank Telescope began in the 1990s, with its huge circular track and support. The track is built 25 feet into the ground to keep the entire telescope sturdy and level. In this photo, contract engineers and staff are tightening the metal plate above the concrete track. Behind them is one of the GBT’s four trucks that drive the 17-million pound telescope around on the track. Each truck has four wheels that support around one million pounds.