There are plenty of swamps in the world, and each one is unique. Most of the time, however, any swamp you happen to visit is going to look at least somewhat similar with various types of trees or other vegetation along with brown, murky water. They can be beautiful in their own way.

That is also what the swamp in First Landing State Park in Virginia looks like for much of the time, but if you plan your trip wisely, you will be welcomed with some vibrant colors that have earned the area the nickname of the “Rainbow Swamp.”

You can walk through the swamp by following the Bald Cypress Trail, which is mostly a boardwalk combined with a nice trail through some dryer areas. As the name of the trail implies, you will get to enjoy the beauty of many cypress trees along the way.

In the late fall and through the winter (unless the water happens to freeze), when the sun is in the right position in the sky, this swamp turns from normal to brilliant. On the surface of the water, you will see a rainbow of colors streaming across. The colors look like someone spilled a thin layer of oil or gas into the swamp since it gives off a similar rainbow color as those contaminants do in puddles of parking lots.

Don’t worry, however, the rainbow on these waters is not from any unnatural pollutants. Instead, it is from the very natural process of rotting leaves.

The many bald cypress trees in the area have needle-like leaves that grow in the spring, boasting a beautiful green foliage. As the fall comes, they turn mostly into a reddish color before they drop down into the water below.

As they rot and decompose, the natural oils are released into the water, causing the rainbow effect. Jeff Ripple is a former Florida swamp walk leader, and he talked to the BBC about this phenomena, saying:

“The rainbow sheens found as a thin film on top of pooled water in swamps and marshes are the result of natural oils released by decaying vegetation or the biological processes of anaerobic bacteria reducing iron in soil. Movement by sheet flow, current or wind disturbance would destroy the fragile rainbow film.”

The process of breaking down the leaves happens in many places throughout the world, but it takes the much calmer and slower moving waters of a swamp to allow the natural oils to stay in one place, concentrated, enough to give the rainbow effect.

Technically speaking, you could get lucky and see the rainbow any time of the year, but due to the freshly fallen leaves and the angle of the sun, late fall and early winter are the best.

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