Bird’s nest — up to $10,000 per 1kg (2.2 lbs)
Edible bird’s nests have been used in Chinese cuisine for more than 400 years. They are believed to be extremely beneficial to health, as hardened bird saliva is rich in iron, calcium, magnesium, and potassium. The most expensive nests are a saturated red color. They can only be found in caves that are rich in nitrogen fumes. When dried nests are soaked and steamed in water, they partially dissolve and become gelatinous.
i swear if you got dirt off the top of mount Everest (or told rich people that's wear you got it from) you could get them to eat it by telling them it has natural nutrients not found at ground level