Perhaps the easiest Second Passport in the world!
There is a little discussed option open to citizens of some western nations that costs practically nothing, and can be the first step towards protecting yourself in many possible scenarios:
A Concurrent Passport.
A concurrent is passport is a second passport that many western countries can issue to their citizens on request, generally it is of lesser duration than your primary passport but can be used in exactly the same way, in all of the same places. For US citizens they only last 2 years and Australian concurrent passports last 3 years.
The reasons for applying for a concurrent passport could be that you are traveling to the middle east and cannot enter certain countries if you have an Israeli stamp, and you may face difficulties in Israel if you have certain Arab countries' stamp in your 1st passport.
You may also need to travel and your first passport is in an embassy awaiting visa approval (Have done that myself :) .
They can be incredibly valuable if you are robbed or illegally detained – you are no longer at the mercy of a foreign government or consulate to issue travel papers, just grab your second passport and go. Get yourself out of danger as fast as possible and then report the problem to your nearest embassy.
This is one of several ways that you can protect yourself and make your travels easier that are completely legal, yet largely unknown.