Is the hubble telescope the biggest telescope ever built?

No, the Hubble Space Telescope is not the biggest telescope ever built. While it is one of the most powerful and well-known space telescopes, it has a 2.4-meter (7.9-foot) primary mirror. The largest optical telescope currently is the Gran Telescopio Canarias, which has a mirror measuring 10.4 meters (34 feet) in diameter. Additionally, the future Extremely Large Telescope is expected to have a mirror larger than 39 meters (128 feet).