Did You Know Facts: The Runaway Elephant
On 21 July 1950, circus director Franz Althoff had Tuffi, then a four year old Indian elephant, take the monorail in Wuppertal, as a marketing gag.
The elephant apparently did not think the gag was that funny. Tuffi trumpeted wildly and ran through the wagon, broke through a window and jumped off the local monorail and fell some 39 ft (12 meters) down into the Wupper river. She lived another 40 years to tell the tale.