Although Beowulf was written in England, in English, it is set in Denmark and Sweden in the sixth century, maybe about the year 500. Some of the places, battles, and people are historical and attested in Scandinavian sources.
Many editions of Beowulf have covers decorated with this helmet:
(Source, Wikimedia Commons). Maybe mine will, as well.
This is a modern reproduction of a helmet found in a buried ship that serves as a royal tomb, buried in the early 7th century (not long after the period when the Beowulf story takes place) and discovered in 1939. It is from Sutton Hoo, in Suffolk, England. It is similar in style to a helmet found in a seventh-century boat grave in Vendel, Sweden.
(Source, Wikimedia Commons).
Sutton Hoo also contains a harp. Beowulf may have originally been performed to musical accompaniment from a harp like this reconstruction of the Sutton Hoo harp.
(Source, Wikimedia Commons)
The fact that kings were buried in ships at Sutton Hoo and Vendel may mean that Scyld Scefing's burial at sea, at the beginning of Beowulf, may be a metaphor for a king's burial in a ship on land. After all, it is not a good idea to shove a ship full of treasure out to sea when the tide may bring it back the next day. The metaphorical journey of the man in the ship is from life to death, not from land to land.
If Heorot existed (Hrothgar did), it is probably at Lejre, on the island of Zealand in Eastern Denmark. Three royal halls have been excavated there: one from the ninth century, one from the seventh, and one from the sixth. All are about 50 m long. More information here. A recent book on this is Beowulf and Lejre by John Niles.