Reading Bertrand Russell's History of Western Philosophy puts some of human kind's biggest ideas in perspective for you:
Big idea #1:
Their [Leucippus and Democritus, 5th century b.c.] point of view was remarkably like that of modern science. They believed that everything is composed of atoms, which are physically, but not geometrically, indivisible; that between the atoms there is empty space; that atoms are indestructible; that they always have been, and always will be, in motion; that there are an infinite number of atoms...
Big idea #2:
Aristarchus of Samos (310-230 b.c.) is the most interesting of all ancient astronomers, because he advanced the complete Copernican hypothesis, that all planets, including the earth, revolve in circles round the sun.
Big idea #3: Aenesidemus of Knossos (1st century b.c.), a sceptic, wrote a short treatise, 'Arguments Against Belief in a God'.
For all these ideas, it took centuries before they reappeared...