Locals kept telling me, "We live in an open society. Wherever there's an open door, you are welcome to enter." And I found that to be the case. Some of my favorite hours in Havana were spent simply strolling down the streets, venturing into back lanes, and popping into courtyards, shops, schools, and bakeries...anything that was open.
Cuba is very proud of its schools. They looked extremely ramshackle compared to American schools. But, unlike in neighboring countries, Cuban children are encouraged to get a solid education (it's compulsory from ages 6 to 16, and free all the way through a Ph.D.). Families are not impoverished by having to pay for tuition, uniforms, and books. Exploring the city, you find many grade schools tucked into big building blocks in the urban core. They all seemed to be named for Revolutionary heroes, with a bust and memorial to each at the entrance. And the children -- with their bright-red kerchiefs -- seemed both enthusiastic about learning and excited to meet foreign travelers who drop in.
Even at midnight, if we happened into a grade school, the guards would jump at the opportunity to invite us in and show us around.