Certain things are non-negotiables for your trip. You will need money. You will need an airplane ticket. You will need an itinerary. You will need a backpack.

You will also need a passport. If you do not have a passport, give yourself a month to secure one. It will not take that long, but having to rush a passport costs money that you can spend on your trip instead.

You may need visas. Check with your local consulate. Americans traveling to Europe only need visas for Russia and Ukraine -- plan three months in advance. If you're traveling to Turkey, you buy a visa at the border.

You generally do not need vaccinations before traveling to any European destinations.