When we think of robots, we mostly imagine them as goal-driven, determined, rational machines. Insofar as they exhibit exploration at all, this is typically to map physical environments so that they can perform their tasks even better. Exploration is hardly ever the primary purpose of a robot, let alone an internal drive...
Discussing a robot's "internal drive" or "motivation" can easily get you stuck in endless debate. Nonetheless, we find it interesting to consider robots that give us the impression of having internal motivations. In particular that most-basic human and animal drive to explore: curiosity.
Here are some curious bots:
(photo at top of page: artwork "Goldie 1971" by Joe McCreary, a robot made from cast iron and steel, nearly 8m long, located at the University of Alabama)