do us citizen require visa for europe?

The only countries in Europe US citizens require a visa are Russia and Belarus. all other countries are visa free for visits up to 90 days (or even 6 months in the case of the UK)

for a tourist stay up to 90 days?US citizen do not need a visa,for any other visa? yes=studend/marriage/work/business or just reside in Europe,which would fall under the categories of visa written above.

Whether you need a visa or not depends on your nationality. The only reliable source of visa information is a consulate of the country you're planning to visit. You'll find a list of foreign consulate offices in the USA at:

You do know that Europe isn't a country right??? At least not yet? It's like 50 different countries. You need to be specific. You could also just do your own research. Visit the web site of the embassy of the country that you want to visit.

Yes, but you don't need to get one in advance if you are just traveling for personal reasons or for business meetings. In those cases they will be stamped in your passport at the port of entry.