As a dedicated runner, I have learned over the years that a great way to experience travel is by lacing up and running in different cities and country sides. As Secretary of Homeland Security, I did a lot of traveling around the country and overseas. Negotiations with foreign governments over travel and trade security and counter-terrorism cooperation took me to Europe, Asia, and the Near East. I visited Baghdad and Afghanistan (but did not run in either). Here at home, most of my travel often focused on areas that were stricken with disasters. But some of those trips did afford me the opportunity to experience running in some remarkable or unusual settings.

The sheer improbability of running along the Gulf—scene of so much international attention—adds unusual interest.

What are the elements of a great run? Cool, dry weather; relatively but not totally flat terrain; soft running surfaces, like dirt, gravel or macadam. A breeze helps. And interesting sights are always a welcome companion to a long run.

Here are five runs I found truly remarkable:

Astoria, Oregon. Astoria, situated near the confluence of the Columbia River and the Pacific, on the Oregon Coast, is the home of the United States Coast Guard's Motor Lifeboat School. Here is where the rescue crews of the Coast Guard train in the roughest waters of the continental United States. On a trip to experience the training, I had the chance to take an early morning run along the Columbia River.The path is formed from abandoned railroad ties, packed one next to the other. The ground surface is flat. What makes this a great run is the cold fresh air, and the backdrop of the majestic river and mountains.Various kinds of river traffic ply the water in the morning and the seagulls lazily preside overhead. All in all, an extraordinarily peaceful setting.

Doha, Qatar. Doha is hot, humid, flat, sandy, and situated along the Persian (or Arabian) Gulf. Not traditionally beguiling running conditions, although Doha was in competition to host the Olympic Games. But the sheer improbability of running along the Gulf—scene of so much international attention—adds unusual interest. The landscape is strewn with truly remarkable examples of modern architecture. The temperature definitely makes the run challenging, but the locale holds your attention.

Rome, Italy. Running along the Tiber is tough on the legs and lungs: The pavement is hard and uneven. And the traffic, which produces a lung-searing exhaust, causes a runner to pause for cars at each of the bridges—or else sprint across. But it's all worth it. Beginning at the Isola Tiberina one passes through extraordinary neighborhoods like the Trastevere and the old Ghetto. Along the way, you can spot the dome of St. Peter's and the massive ornate Italian high court building. Depart the river for a short distance to finish up at the Circus Maximus—a loop of less than a mile that’s not particularly pretty, but still the original site of chariot racing. You feel as if you are running in the footsteps of Ben Hur himself.

London, England. Running Hyde Park in the early morning affords a blend of sights, sounds, and, yes, smells. You share a comfortable hard-packed dirt track with the horses getting their workout courtesy of the Queen's Cavalry. The grass is lush and green, and the park is framed by the stateliness of Park Lane. On a Sunday run you can catch some of the opinions being aired at Speaker's Corner. In the park you will also find the Serpentine, a lake in which people boat or swim (depending on the time of year). One exit from the Park will take you past a unique war monument—pay your respects at the animal memorial dedicated to those horses and dogs who have served with the Armed Forces.

Rio de Janeiro, Brazil. Although Rio conjures up many images—Carneval, Ipanema—it also ought to trigger an association with running. Imagine my surprise on a Sunday morning to see that the city shuts down the roadway along famed Ipanema beach and it fills with runners of all ages. Framed against the breathtaking vista of the ocean and the mountains, the course is straight, flat, relatively forgiving macadam and unbroken by traffic. The crowds do not make this ideal for speed work, but the variety of sizes, shapes and costumes afford remarkable distraction. Run while listening to Astrid Gilberto signing Brazilian jazz.

Michael Chertoff was the second Secretary of Homeland Security. He previously served as the Assistant Attorney General for the Criminal Division at the Department of Justice. As Assistant Attorney General, he oversaw the investigation of the 9/11 terrorist attacks. He also formed the Enron Task Force. He is currently senior of counsel for Covington & Burling LLP's Washington, D.C. office and a member of the White Collar Defense and Investigations practice group.