Most small-molecule neurotransmitters are stored in small vesicles that range from 40 to 60 nm in diameter and, in electron micrographs, appear to have clear centers. The vesicles that store neuropeptides are larger, ranging from 90 to 250 nm in diameter.
The world's largest concentration of natural sandstone arches. 1  Hike the 1.5 mile trail leading to the base of Delicate Arch to experience one of the most breathtaking vistas in the world. 2  Your family will love the short trails in the Windows Section that lead right up to several massive arches.
The Arch has foundations sunk 60 feet into the ground, and is built to withstand earthquakes and high winds; it sways up to 1 inch in a 20 mph wind, and is built to sway up to 18 inches. A Grand Staircase leads from the St. Louis levee up to the base of the Gateway Arch. Fees are charged to ride the unique tram system to the top.