What should a pilot do if he does not know where he is and has no form of communication?
The first thing you should do during a lost com's situation is fly the plane (that is really the first thing you should always do). 

The second thing you should do is use visual reference points to figure out where you may be and get some situational awareness. Even in a foreign land a pilot may be able to identify known land marks like city skylines or prominent geological features. Even something like a coast line can be identifying. If the pilot becomes concerned about fuel (which any good pilot will at some point) then they should be on the look out for an airfield or a nice area to put the aircraft down. 

The third order of business is to squawk 7600 on your transponder. This will alert any ATC facilities pinging you on radar, that you are unable to transmit and/or hear them. 

This falls in line with the FAA's general advice of "Aviate, Navigate, Communicate".

Just a bit of an applicable side note: In the US under the FAA, and in other jurisdictions there are lots of areas that full under "uncontrolled" airspace where no radio or charts are required to be onboard anyway and many pilots are proficient flying in such a situation. Id even go so far as to say that a solid chunk of Piper Cubs are still flown this way.