According to the Centers for Disease Control and Prevention, some form of diarrhea hits nearly half of all seniors who venture far away from home. Some call it Montezuma's revenge, but when it happens to you, there’s nothing funny about it.

There are three basic kinds of diarrhea: viral, bacterial and, especially for traveling seniors, sudden changes in eating habits. The kind that hits most often is bacterial, and named for the ancient Mexican emperor because it comes from unclean foods, sometimes from the land south of our border.

Mexico is accused, often unfairly, of having poor sanitation standards. However, on any travel away from home, seniors should do their eating at higher-scale, clean restaurants.

It isn't easy to pick the top ten in a world full of great destinations, but we can name some seniors should NOT visit.... Tehran, Baghdad, Kabul ... nah, enough of the negatives. Here’s a quick list of ten favorites:

1. Las Vegas NV: Once in Sin City, the world is yours! You don't need to go anywhere else. For Broadway, check into the New York New York Hotel. For France, visit the Paris Resort. For Italy, go for Bellagio and The Venetian Hotels. For Caribbean, surf at Mandalay Bay. For classic Rome, march into Caesars Palace. For ancient Egypt, try the Luxor.

Some of the best entertainment and dining in the world can be found just within a few blocks on the famous Las Vegas Strip. While strolling there, and all for free, you can see the night light up by an erupting volcano, a sky-high ferris wheel and much, much more.

2. New York NY: If you can make it there, you'll make it anywhere. It’s up to you to take full advantage of the Big Apple. The city that never sleeps offers posh Manhattan hotels, endless world-class Broadway entertainment, exotic dining and scads of upscale shopping on Fifth Avenue.

Q: I recently boarded a flight, and was surprised to see a big German Shepherd dog stretched out on the floor inside the first row of seats. His harness plate ID showed he was a service dog. During the flight, he sat between the bulkhead and his blind master’s feet.

He looked very calm, as if flying was no big deal. I know service dogs are permitted to ride in the passenger area on U.S. flights, but what about other countries? ADF, Minneapolis MN

A: In 1940s and 1950s Navy duties, your travel4seniors.com editor rode in some third-world flights with chickens and goats wandering the aisles. Of course, it has become a bit more sophisticated since then. U.S. airlines allow documented service dogs to ride in passenger cabins.

For people who must travel beyond the U.S. in foreign airlines with service dogs, it’s necessary to check the rules. If you or a companion intend to bring a service dog, first contact the embassy or consular offices of countries where you’ll be visiting.

Generally, find parks and other areas that don’t involve too much crossing of busy streets, especially if you’re out during heavy drive times.

For example, start at the National Mall, where you can run the two miles around the perimeter from the Capitol steps to the Lincoln Memorial. Or ventune into the Reflecting Pool area where there are always interesting events, such as political rallies, exercise classes and school groups.

You can jog past DuPont Circle and up Embassy Row from Massachusetts Avenue, observing the stately lines of elegant buildings and imagine all the political intrigue and posh social events you'll never get to see. If you happen to jog around the Capital Hill area on a Saturday or Sunday, you may see the outdoor street marketers offering fresh veggies, baked goods and old family heirlooms.