[Lee Stewart]

Although it's the soup made with the nest that's the delicacy rather than the actual nest, they're still notoriously expensive – not to mention controversial. Made by cave swiftlets by binding moss, seaweed and feathers with their saliva, the nests can sell for as much as $4,000 for a kilogram (2.2lb). However, unethical practices by irresponsible farmers have prompted import restrictions and regulations from governing bodies in countries such as China, who have also introduced strict rules to improve the safety and traceability of the goods.