'Vikings: Valhalla' is a sequel to the original 'Vikings' series, set over a century later and following the adventures of a new generation of Norse explorers and warriors. Watching the original 'Vikings' series enhances your viewing experience of 'Valhalla' as it provides valuable context about the Viking Age, the cultural and religious shifts of the time, and the legendary figures from the first series, such as Ragnar Lothbrok and Lagertha. The original series establishes the groundwork for the Viking world, including its customs, values, and the challenges they faced, which continue to resonate in 'Valhalla.' Moreover, the emotional arcs and legacies of the characters from 'Vikings' significantly influence the motivations and relationships in 'Valhalla.' Therefore, while 'Valhalla' can stand alone, viewing 'Vikings' first offers a richer understanding and appreciation of the narrative continuity and thematic depth, enhancing the overall experience.