Penrhyn is the largest slate quarry in the Slate Landscapes of Northwest Wales World Heritage site. Exploitation of slate began in the sixteenth century but grew substantially with the investments of Richard Pennant after 1785 with profits from slave-worked sugar plantations in Jamaica. At the end of the nineteenth century it employed 2,800 people and exported roofing slates worldwide. The quarry still produces high-quality building materials. Zip-World opened a zip-wire ride across the quarry in 2013 (its first of several in north Wales). It offers tours of the quarry by passenger lorry. Visitors are taken to the highest part of the quarry at 450 m above sea-level, where there are views across the Snowdonia mountain range. The quarry pit is 370 m deep and 1.5 km across, exploited by benches cut into the rock. Large tips of waste rock and the sites of processing mills also dominate the landscape. Slate was raised at different times by inclined railways, aerial ropeways, two water-balance lift shafts, and more recently by lorry.