There is not a single Europe visa. Europe has many countries and it will depend on where you are coming from and which countries you are going to as to what visas you will need.
If you are coming from the United States you do not need a travel visa to visit Europe. I was there earlier this year--you can travel from Sweden to Italy and cross from Lithuania to Finland without ever showing even your passport.
In fact, I tried to get Swedish customs officials to stamp my passport just to collect the stamp. They replied, "that is so old fashioned. We do not do that anymore."
If you plan on staying in a country for a length of time, you will need a visa for that particular country. Consult your embassy for information on that.