A boatswain's whistle, attached to a five-and-a-half-foot gold chain, was among the incredible treasures recovered from the Santa Margarita. The recovery of the ship, which sank off the Florida Keys in 1622, was documented in the February 1982 issue of National Geographic.
PHOTOGRAPH BY DON KINCAID, NAT GEO IMAGE COLLECTON
In this photo from the July 1975 issue, scientists round up tundra swans in Blackwater National Wildlife Refuge, Maryland. The birds, sometimes called whistling swans, were giving tracking bands so that their migration patterns could be studied.
PHOTOGRAPH BY BIANCA LAVIES, NAT GEO IMAGE COLLECTION