If you are interested in learning more about the types of receptacles used in Europe, try this website.
There are a number of different types of three prong, grounded) receptacles used on the European continent (also in the UK and Ireland). Most countries use Schuko receptacles, the type E (French), which has a protruding ground pin, or the type F (German), which has ground clips on the sides of the recess). A lot of grounding plugs and adapters will work in both type E and type F receptacles. Actually, except for Switzerland and Italy, the entire European continent uses one of the Schuko receptacle. I understand, but have not seen, that a lot of new installations in Italy now include both the traditional Italian, type L grounding receptacle and a type F Schuko receptacle.
The Swiss type J receptacle is unique in Europe because it is "polarized", that is, the neutral or ground potential pin socket is always on the same side. American polarized plugs (one blade wider) can be safely used with a grounding Swiss adapter. No other European receptacles is safe for use with an American polarized plug.
The 2 pin, ungrounded Europlug can be used in any European receptacle. However, it's use is limited by code to appliance drawing no more than 2½ amp (no hairdryers). Further, because it is bidirectional (can be inserted either of two ways), it cannot be polarized. Even though most Europlug adapters accept American polarized plugs, they shouldn't. American appliances with ungrounding, polarized plugs cannot be safely used in any receptacle in Europe, including in Switzerland!