Within the hollowed out sandstone, rivers and pools of water are met with little sunlight; conditions that allow algae to flourish and turn the water into its greenish/turquoise hue. Careful to be too lured in by the algae though, as it also coats much of the surrounding sediment, making for a slippery obstacle to dance around while hiking. Other wildlife within the tunnel includes an abundant population of dragonflies, frogs, lizards, and some species of birds. In fact, the surrounding Zion National Park is home to more than 270 species of birds, including the infamous roadrunner.
As beautiful as the Zion Subway may be, caution must be taken when hiking through, as conditions in the tunnel are known to escalate quickly. Danger from flash-floods, extreme heat, and hypothermia does put adventurists at risk but shouldn’t deter everyone from venturing into the Zion Subway tunnel. Although the hike may require extensive preparation and training, the payoff of visiting one of the desert’s best kept secrets is well worth while.
Christian Bothner, National Geographic