Other than Native Americans, who else arrived in America before the Europeans

The corresponding time unit is the mean solar day dm. With the aid of clocks, dm is further divided into 24 hours of 60 minutes, each minute being in turn divided into 60 seconds. The definition of the duration of the second as the 86400th part of the mean solar day basically was arbitrary, and part of our tradition.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

the idealization of the rural landscape ; admiration for the beauty of nature ; focus on an individual's inner concerns