Here are The Traveling Professor's recommendations for 5 essential items a traveler should carry on an international trip:
Travel Health Insurance and Emergency Evacuation Policy: Fortunately, on my trips, we have not seen too many travelers need to use these policies, but when they do, they can literally be lifesavers. Chances are, your domestic health insurance policy will not cover you while overseas, especially for emergency evacuation. But over the years we have seen sprains, some travelers had to have a few stitches, and others needed to visit the hospital or a dentist. Having medical coverage saved a lot of money and guaranteed quick access to medical attention. What travelers REALLY need is medical evacuation insurance. We had a traveler tell a story of a trip he was on (not a Traveling Professor tour) where he slipped and broke his hip on the last day of the tour. In order to be treated back home in North America, he needed to be medically evacuated from Europe at a cost of about $75,000. That's right, $75,000. It was covered by his medical evac insurance. For more insurance info, see www.safeguardtravel.com
Copy of Passport: Unless necessary, don't carry an original passport around the streets of Rome, Paris or any other destination. However, carry a copy of a passport. Write down medical conditions, contact info of people back home, and the name of the hotel you are staying at.
Extra Meds: During Hurricane Sandy, we had travelers stranded in Europe for nearly a week. During the volcano eruption in Iceland, we had travelers stuck for an extra 3 days in Paris. The point is, you never know when there will be delays and interruptions, so take extra meds.
Global Entry/TSA Pre-Check Card: Waiting to get through security on trip departures from the U.S. this summer looks like it is going to be brutal. Coming back to the U.S. to go through passport control might be worse. Get enrolled in the Global Entry and TSA Pre- Check program and avoid waiting in horrendous lines.
Smart Phone with Communication Apps Like Skype or WhatsApp or a Texting/Messaging App: Data plans can be expensive overseas but most hotels have free wi-fi and sometimes cities (Florence comes to mind) provide visitors with free w-fi all over the city. We have found this more and more essential in order to find fellow travelers if they get separated. It's also essential to communicate with those at home.