Three portfolios (Bristlecone, Death Valley, and Almost Ghost Towns) are about the arid eastern edge of California. The character of the area was shaped by millennia of increasing dryness that caused forests to move up the mountains to become desert islands. This area was lightly inhabited before the invasion in the 19th century by those seeking mineral riches. As the extraction of gold and silver and other precious metals ran out, the mining towns shrank and died. The lowest areas of eastern California are the hottest and driest.