Not only variables must be declared with the smallest possible scope. This also applies to types, structures, enumerations, constants, classes etc.. For example, if an enumeration is used for a return value of a member function, the enumeration is defined in the scope of the class.

class CMyClass
{
public:
    enum MyReturnValue
    {
        MYRETURNVALUE_1,
        MYRETURNVALUE_2,
    };

    MyReturnValue
    Foo();
};