There aren't a lot of public buses in Cuba. The local alternative has been to use big trucks – small crowds of people gather on the side of a street, then clamber onto the back of a truck. Fortunately in Santiago de Cuba, where this photo was taken, it doesn't rain too often.
In Havana, where the city is bigger and the weather is a little colder, they use a truck known locally a "Camel". It is an articulated truck towing a large bus-like trailer unit.