The neutral charm meson (the D0) was discovered 30 years ago. Like the neutral strange and bottom mesons, the D0 meson is expected to undergo quantum mechanical "mixing" with its own antiparticle. However, mixing in the D0 system is very suppressed due to the GIM mechanism. Over the past several decades, many experiments have searched for signatures of mixing in the D0 system. I will present the latest results of a BABAR study of D0 -> K pi decays that shows evidence for D0-D0bar mixing with a significance of 3.9 standard deviations. I will compare these new results to earlier studies and to recent results from Belle. These measurements of charm-meson mixing provide a new probe of the Standard Model of particle physics.