Short answers, pulled from the story.
The Jelling stones are two massive carved runestones from the 10th century, standing in the Danish town of Jelling. They are considered the best-known runic inscriptions in Denmark. In 1994, UNESCO inscribed them on the World Heritage List, along with the nearby burial mounds and a small church.
King Gorm the Old raised the smaller Jelling stone in memory of his wife Thyra. His son, King Harald Bluetooth, raised the larger stone to celebrate his conquest of Denmark and Norway and the conversion of the Danes to Christianity.
Art historian Rudolf Broby-Johansen coined the phrase "Danmarks daabsattest," meaning Denmark's baptismal certificate, in the 1930s. The nickname frames the larger stone as the official declaration of Denmark's conversion to Christianity and entry into Christendom as a unified kingdom.
In 1997, a photograph of the larger Jelling stone inspired engineers to name their wireless technology Bluetooth. The stone was raised by King Harald Bluetooth, and his name was adopted for the technology.
Three faces cover Harald's runestone: the runic inscription, a crucified Christ entangled in branches, and a serpent wrapped around a lion. The Christ figure has often been read as echoing Odin, who in Runatal describes hanging from a tree and being pierced by a spear.
The Heritage Agency of Denmark chose a protective design from 157 competition entries, with Nobel Architects winning the commission. Their glass-and-bronze casing, mounted on a steel skeleton, creates a climate system that keeps the stones at a fixed temperature and humidity. The glass carries an anti-reflective coating that gives the exhibit a greenish hue.