The second week of Fortnite Season 6 has added a number of new challenges, and one of them tasks you with visiting all of the corrupted areas on the map. These areas are marked by the runes that were left by the cube during its tour of the island throughout the end of season five, and can be found on the map below.
To earn the five Battle Stars for the challenge, just visit each of the areas marked on the map. This can be done in any number of matches. While you're at it, pick up some Shadow Stones while you're there to finish off the "Use a Shadow Stone in different matches" challenge as well.