As you travel up and down the Caribbean coast, you might see Kogi people hopping on local buses with bags full of seashells – but they're not collecting them as ornaments. The indigenous groups of the Sierra Nevada de Santa Marta collect them for a sacred, ritualized method of consuming coca known as the poporo.

The active alkaloids in coca leaves are a powerful stimulant when chemically refined into cocaine. When the leaves alone are chewed, they have little effect. However, when chewed together with an alkaline substance, their active ingredients are multiplied, enabling users to walk many miles without rest or food, even at altitude – handy if you live in the world's highest coastal mountain range.

For the poporo, thousands of seashells called caracucha are collected, roasted over a fire and pounded into a fine powder. This powder is then placed into a hollowed-out gourd known as a totuma, which represents femininity. Men receive this as they come of age.

Women of these tribes collect coca leaves and dry them by placing them into mochilas (woven, bucket-shaped shoulder bags) packed with hot stones. Men take a large wad of leaves, put them into their mouths, and dip a small stick into the totuma to gather some of the powdered shell, which they suck off the stick. Any excess spittle-and-powder mix is wiped on the outside of the gourd, causing it to grow – symbolizing wisdom. The men then chew the mixture for up to 30 minutes; as their basified saliva causes the coca leaves to release their active components, users experience a slightly cocaine-like high. It is believed that the poporo instills knowledge, just as reading a book or going to college increases students' intelligence.