White coral sand & empty seashells on a solitary beach. We don't often realize they're the remains of what used to be alive, from a time that has long passed.
Corals are the reef-builders of the sea, building vast undersea structures that are the equivalent of rainforests on land. When they die, their skeletons are eventually pounded into smooth pebbles or fine sand that one day is pushed ashore to form gleaming stretches of beach. Empty seashells once belonged to something alive, the very presence on which on a seashore tell us what animals live (or used to live) in the waters beyond it.
I consider them as "blasts from the past", gifts left behind for the observant few who have come to ponder their existence. By asking the same questions of ourselves, hopefully we'll cherish life just a tad more, however short and transient it already is.