Unusual Post offices in the World

Post Office Bay, 
Island of Floreana, Galapagos Islands, Ecuador

Running since 19th century as a mail delivery system; Here Sailors used to put the Unstamped Letters written to their families in a Barrel. Other ships on way back to their home Port UK, USA etc picked up the letters destined to their nearby place & deliver them. That tradition continues; now Tourists use this Post Office Bay to send Unstamped letters home to themselves or their loved ones & receive them via personal delivery from other tourists.