Since the museum opened its doors to the public in September of 1994, its greatest treasure are its painting. The world's most important collections of works by artists Diego Rivera and Frida Kahlo are housed here permanently and are adored by the legions of visitors who flock to admire them. There is, as well, a collection of the woodcuts and book illustrations by Russo-French painter Angelina Beloff, Rivera's companion during his early years as a budding painter in Europe.