Subdivisions. The Ordovician is the second period of the Paleozoic era. The Ordovician began after the end of a series of extinction events known as the Ordovician-Silurian extinction events which ended around 488 mya.
As a state highpointer, Humphrey's Peak in Arizona was on my bucket list. The trailhead was easy to find. The trail itself was not well maintained and rather rocky, which wasn't too bad going up, but required a lot of caution descending to protect your knees.
It is also the tallest building in the state of Arizona. The second-tallest building in the city and the state is the US Bank Center, which rises 407 feet (124 m). Of the 20 tallest buildings in Arizona, 18 are located in Phoenix. The history of skyscrapers in Phoenix began with the completion in 1924 of the Luhrs Building, which is regarded as the first high-rise in the city; the structure rose 138 feet (42 m) and ten floors.