On May 10, 1869, the first transcontinental railroad route across the United States was completed, ushering in a new era of transportation.

Radios blaring the melodies Fleetwood Mac may have inspired parents to name their daughters after the band’s keyboardist, Christine McVie, people who came of age during the peace-and-love counterculture revolution may have been attracted to nature-inspired baby names, like Crystal, April, or Heather.

So why were so many parents drawn to a few popular names during this groovy decade? The answers vary from name to name but make total sense when you consider the context of the era.