Scientists have unearthed five bone-made instruments dating to the 18th century which they say are finely crafted telescopes that may have been used to gaze at objects on land or sea. Ranging in length from roughly three to five inches, the telescopes -- discovered in Amsterdam, the Netherlands -- were made using cattle metatarsal bone. At the time, called the Enlightenment, the telescopes would have been considered luxury items and were likely used to gaze at objects on land or sea, rather than to look at the stars. They were created during a period when Amsterdam was a flourishing centre for trade, one that attracted talented craftsmen. Read more