"The Overwhelmingly Large Telescope (OWL) was a conceptual design by the European Southern Observatory (ESO) organisation for an extremely large telescope, which was intended to have a single aperture of 100 metres in diameter. Because of the complexity and cost of building a telescope of this unprecedented size, ESO has decided to focus on the 39-metre diameter Extremely Large Telescope instead."

https://en.m.wikipedia.org/wiki/Overwhelmingly_Large_Telesco...