A glow from the Bioluminescent Bay in Vieques, near Puerto Rico.
Last fall, Maryland residents Jessica and Richard Johnson left the Eastern Shore on a yearlong sailing expedition with their daughters, Emma and Molly.
Since then, they've traveled thousands of miles down the Atlantic Coast and into the Caribbean. And they've seen some remarkable sites, including a bay whose waters are famous for a one-of-a-kind, glowing bioluminescence.
"Elcie is anchored on the south coast of Vieques," says Jessica Johnson. "It's an island that belongs to Puerto Rico, and it's not too far east of the main island of Puerto Rico."
Vieques is home to several "bioluminescent bays," which light up at night because of the existence of tiny half-plant, half-animal organisms known as bioluminescent dinoflagellates. When you touch the surface with your hand or a kayak paddle, Johnson says, the water lights up with flashes of light.
Johnson says visitors are prohibited from using boats with gas engines in the bioluminescent bay because they can be harmful to the organisms that live there. That means visitors are surrounded instead by the sounds of frogs in the nearby woods, and by a particularly unusual form of natural light.
"Apparently the bay here is the brightest one in the world, and apparently it's a really good time to be here and see the bioluminescence, because yesterday was the new moon, so today it's almost completely dark," she says.
Visiting the bay had a big impact on the Johnsons' daughters. "This is probably one of the most amazing things I've ever seen," says Emma, 12.
[Music: "Mothersbaugh's Canon" by Mark Mothersbaugh from The Royal Tenenbaums / "I've Got the World on a String" by Tal Farlow Quartet from Cookin' On All Burners]