So I'm a bit confused because the structure of higher education is different in America than it is here. In the States the typical undergraduate degree (for example in physics) is around 4 years. From what I heard, most students who end up getting a doctorate go straight to "grad school" after their undergrad degree. However in Europe, according to the Bologna Process , the 3 year Bachelors is usually followed by a 1-2 year Masters program before enrolling in a Phd program.
The question is, how are these 2 systems of education compatible? Let's say I want to do my physics Phd in the U.S., would I need to have both my Bachelors and Masters degrees before applying to a "Grad School", or would a bachelors suffice?