No, not a joke, it happened. I just saw it on the news so I thought I would bring it here.
Just a little background. Circus Knie is the national Swiss circus and has been in the family Knie for many generations. You can say a Swiss institution. Throughout the Winter they are in the town of Rappiswil on the Lake of Zürich, but in Summer they tour Switzerland, starting their tour traditionally in the town of Zürich situated on a square known as Sächseleutenplatz. So yesterday they were planning departure from Zürich and one of the elephants decided to do a sightseeing trip before they left.
Here is a link to a small video taken by a passer-by
Sabu the elefant takes a walk through Zürich
and here a report from the Daily Mail, although they seem to have some confusion with a photo where they mention the lake of Geneva which is actually 3-400 kilometers away from Zürich. It was taken of the elefant in the lake of Zürich.
Daily Mail report