Neither Rain Nor Sleet Nor Depth of Sea...

Although a couple more underwater mailboxes have popped up around the world, the post office box at Vanuatu lays claim to being the first such operation. It's 10 feet beneath the surface, about 160 feet from land, and is an actual post office box that will receive your special waterproof plastic postcard, marked with a special embosser so the postmark ink won't smear.

If you want to do the real experience, you have to snorkel, dive or hold your breath long enough to go below and float your card into the slot. Or you can ask someone able to do those things to drop it off for you. (There's also a land-based box for the wimps).

Then, at 3 PM each day, the mail is collected from the box to be sent off to its destination. The local post office used to train its folks to scuba dive so they could pick it up themselves, but found it easier to enlist the aid of local dive masters who could pick the mail up for them.

The story at Smithsonian says that the box in Malaysia is 130 feet below the water, which is the maximum depth for a certified, experienced recreational scuba diver using tanks with normal compressed air.

And it would seem that the most unsurprising thing about this whole idea is its origin: The local postmaster and a resort owner whipped it up over drinks.