Back when the U.S. was still part of Pangea more than 200 million years ago, Arizona was located near the equator where Costa Rica is now, and it was covered in tropical forest. When the trees of that ancient forest fell, they became water-soaked and that water became crystallized into quartz over time. Today those rock-trees lie strewn about in pieces throughout the Petrified Forest National Park. As the supercontinent broke apart and shifted into the continents we know today, that once tropical forest moved to present-day Arizona, where desert erosion has begun to uncover the petrified logs that were buried in sediment long ago.

After stopping at the visitor center, we took the Painted Desert overlook loop. The drive and overlooks provide great views of colorful desert formations. Then we drove through the park on a preserved section of Route 66, stopping at Crystal Forest for an amazing up-close look at petrified wood intact in its natural state. Dogs are allowed on trails, leashed.

As with all of the national parks and protected sites we’ve visited on this trip, we previously had only an inkling of appreciation for these natural wonders before we saw them in person. Standing up close, running our fingers over them, put into perspective the monumentous occasions of time and natural process that went into creating these small artifacts of earth’s history.

In contrast to the natural history of the Petrified Forest’s wood-turned-stone, the petroglyphs of Painted Rock share a glimpse of early human history. Petroglyphs cannot be directly translated, and the motivations and meanings behind them have been lost to time. Apparently native descendant communities still visit them, but to the majority the etchings remain a mystery. Some of them are easily recognizable, such as lizards and humans. They could be related to vision quests and/or warn of dangers on the path ahead. Petroglyphs also exist at Petrified Forest, but we didn’t visit them there, since we’d already toured these at Painted Rock in Gila Bend, AZ.