Math is Beautiful, math is the absolute truth and that makes it beautiful. Mathematicians even go so far as calling it an art form.
mathematics, rightly viewed, possesses not only truth, but supreme beauty — a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show - Bertrand Russel
One of the most amazing equations, in my opinion, is the Lorentz factor,
Virtually all of the mathematics behind Einsteins theory or special relativity can be reduced back to this one, simple equation. basically, these few lines describe exactly what happens when you travel close to the speed of light, and the fact that it is as simple and short as it is, is beautiful.
Einstein’s search for general relativity spanned eight years, 1907-1915. Some periods were quiet and some were more intense. The moments when the great transition occurred, came sometime between the late summer of 1912, when Einstein moved from Prague to Zurich, and early 1913.