In West Africa, certain villages have markets that "assemble" at regular intervals, such as weekly or every three days. People from villages around the region converge on the town of Djibo in northern Burkina Faso every Wednesday to buy and sell food, livestock, and other goods and services. Here, a woman arrives in Djibo on foot, carrying fresh milk for sale in a calabash. She pauses to bring the calabash to the ground to show a potential buyer.