According to ancienthistory.about.com, Julius Ceasar minted over 22 million 'Elephant Denarii' celebrating military campaigns against the Gauls, or, perhaps, general triumph of Rome over evil forces. These interpretations date the coin somewhere around 50BC to 50AD. The symbols on the back are all Roman religious symbols.
The specimen in our picture is in well preserved condition and comes from Stack's Bowers and Ponterio where it sold in 2013 for $980 US dollars.
Genuine examples of this coin catalog roughly as follows:
worn: $150 US dollars approximate catalog value
average circulated: $500
well preserved: $1500
But beware. With such a notable Ceasar and such a cool elephant, counterfeits of this coin are all over the place, and counterfeits are worth zero. Our secondary picture shows a typical fake, although many other fakes are known to exist.
Coin collecting is a Buyer Beware proposition. Never spend any significant amount of money unless you trust the person you are dealing with explicitly.