A tenderly decorated grave discovered in Alaska holds the remains of two infants dating back 11,500 years, the youngest Ice Age humans yet found in the Western Hemisphere, archaeologists say.

Interred together inside an ancient residence, one child was about 12 weeks old at the time of death, the other, a late-term fetus — the first known instance of a prenatal burial in the Americas.

Researchers say that the babies were memorialized with an array of goods that was, by Paleoindian standards, rather lavish.