THE KEY TO A GOOD TRIP is of course a bad start. So things began looking up for me in Cuba late on my fourth night, when I was ambushed by two young men. They smashed me against the door of my guesthouse, grabbed my wallet, and took off sprinting.

I went after them. Nobody has a gun in Havana, or practically anything sharper than a butter knife, so this isn't quite as stupid as it sounds. I ran hard, chasing them through the quiet city center, screaming for help. After a block I kicked off my flip-flops and started closing the gap, but it was too late. The boys leaped onto their escape vehicle, a Flying Pigeon, one of the 1.2 million bicycles imported from China in the early 1990s, part of Cuba's move away from fossil fuels toward nonpolluting transport. The Flying Pigeon weighs about 55 pounds, but we were headed downhill now, past the University of Havana, and with one boy pedaling and the other standing on the pegs, they squeaked into the night.

For the next two weeks, things just kept getting better. I went scuba diving and blew out my eardrum. A guy dropped an air tank on my foot. The bloody, four-inch scrape on my left arm, souvenir of the mugging, turned green and filled with pus. I was bitten by a crab, rafts of mosquitoes, and two dozen sand mites. Although I'd come here to measure Cuba's environmental situation in the twilight of Fidel's reign, many of the greens I was looking for were in hiding, or jail, or exile. People kept whispering that everything was a lie. I looked up an old friend; he'd become an alcoholic. It was June, and even the weather was bad: windless, humid, and blistering.

Ah, Cuba, mi amor. Dreams are duty-free, imported with our carry-on bags; disillusionment is the national export. We bring the paradise, Cuba supplies the music and mojitos, the good scuba diving, the confounding moral examples, the surprisingly intact ecosystems, and—ouch!—a quick and bloody mugging, all accomplished with amazingly bad equipment.

This was my lucky 13th visit. Things may start off badly, but in Cuba the future is always glorious. No matter how much they beat on me, I will say it again: Everything is splendid in Cuba. Don't believe otherwise, no matter what I tell you.