Home to more than 2000 natural sandstone arches, Arches National Park is a stunning place to visit. The park sits atop a salt bed that is thousands of feet thick in places. Under pressure the salt is unstable and shifts, buckles and liquefies thereby thrusting the rock layers upwards as domes and whole sections fall into cavities. As well as the arches, there are many other unusual rock formations from towering spires to fins and balanced rocks. The Park Avenue area is so named because it looks like skyscrapers in the city. They were formed more than 150 million years ago by tidal flats, desert and beach deposits. One of the most amazing things we learned is that the softest rock is on the bottom! When you look closely at some of the photos you can see what we mean. No wonder there are so many unique shapes as water, ice, extreme temperatures and underground salt movement continue to sculpt the area. While many of the arches are not visible from the road in the park, new ones are constantly being created while others are eroded away. The arches are usually created from narrow sandstone walls called "fins" and water seeps into the cracks then freezes and expands causing chunks of rock to fall off. Gravity and erosion help complete the formation of the arches. About halfway through the park there is a huge area of Petrified Sand Dunes which were created by northwest winds blowing fine grained sand into the area. Over thousands of years the drifts were covered by other sediments that have been slowly eroded away leaving the petrified dunes. Probably the most famous arch is the Delicate Arch which stands alone at the edge of a bowl and is 46 feet high and 35 feet wide. Looking around the park at the array of unique forms and shapes you can't help but wonder if in another 150 million years the region will once again return to sea level and be covered by water or will volcanic activity return with fire and lava to create a new landscape or will it become an area covered with forests, waterfalls, and canyons. We'll never know!