There's a mystery sitting in the Clarendon Laboratory at Oxford University. There's a bell in the lab that has been ringing nonstop for more than 175 years. It's known as the Oxford Electric Bell, and no one knows how it has been ringing for all these years. All that's known is that a battery was installed inside the bell in 1840, but researchers would almost certainly ruin the battery's streak if they opened it to find out what's going on inside.
According to the university, the bell, which is powered by this single, seemingly immortal battery, has rung approximately 10 billion times. The battery is what's called a "dry pile," which is one of the first types of electric batteries. These work by use alternating discs of silver, zinc, and sulfur, plus other materials, to generate electricity. In the case of the Oxford Bell battery, the makings of the "piles" inside the battery is not known. The Guinness Book of World Records has named the Oxford Bell as the "world's most durable battery." Discover more about this mysterious bit of technology, and other batteries, in the video below.