The Maya were amazing astronomers.

From observatories atop their great pyramids, they charted the path of Venus and calculated solar and lunar eclipses with an accuracy that would not be matched for many centuries.

They were equally skilled as mathematicians. Maya scholars developed a number system that used only three symbols: a line for five, a dot for one, and a shell for zero. The idea of using a symbol to stand for zero was invented by these ancient mathematicians.

They also were the first to use negative numbers.