Sometimes fragments tell more of the story.

From the Cleveland Museum of Art :

At approximately 1:00 am on March 24, 1970, a bomb irreparably damaged the Cleveland Museum's version of Rodin's The Thinker. The bomb itself had been placed on a pedestal that supported the enlargement and had the power of about three sticks of dynamite.

No one was injured in the subsequent blast, but the statue's base and lower legs were destroyed. The remaining sections of the cast were blown backward to form a 'plume' at the base, and the entire statue was knocked to the ground. It was reported that this attack was undertaken by a radical political group, perhaps as a commentary on the continuing military action in Vietnam or the elitism of the American government.

Regardless, no one was ever arrested or charged with the destruction. However, the incident highlighted several conservation issues related directly to artistic intent. Since the piece was so dramatically damaged, the Museum was unsure how to proceed. One idea was to create an entirely new cast to replace the damaged work. Another idea was to restore the sculpture by recasting elements of Rodin's original. Finally, however, it was decided that the statue should not be repaired, but placed outside the Museum in its damaged condition.