>All of the (in retrospect) misguided attempts to prove Euclid's Parallel Postulate, which eventually lead Gauss to develop hyperbolic geometry. I had geometry

>All of the (in retrospect) misguided attempts to prove Euclid's Parallel Postulate, which eventually lead Gauss to develop hyperbolic geometry. I had geometry last year and we mentioned that a lot of mathematicians tried to prove Euclid's Parallel Postulate. They tried adding a lot of properties to geometries. Saccheri is worth mentioning for contributing a lot in this development, especially for Saccheri quadrilateral!