Piaget Altiplano In 2016, the Swiss watchmaker launched the Piaget Altiplano (high plane in Spanish) 38 mm 900D, marketed as the world’s thinnest manually-wound mechanical watch (5.6 mm), with the case, crown and dial set with diamonds. It is meant for those interested in high-jewellery watches and is the newer version of Piaget’s 3.65 mm thick Altiplano 900P introduced in 2013. The 18K white-gold case comes with an extra bezel structure which is set with baguette-cut diamonds, while the rest of the case sides are set with round-cut diamonds. This special high-jewellery edition retails at around 153,000 euros