Re: strange site
Exactly. So, drawing inspiration from Redmenace's suggestion of a Lovecraftian setting, here's my idea:
An evil cult whose members are posing as druids is attempting to take control of all megaliths located at the nexus points where ley lines cross. By controlling these points, the cults are able to summon beings from the outer dark. Stonehenge being the best known and most accessible, the campaign starts with the "druids" performing a ceremony at the summer solstice (or any other appropriate time of year) to conjure a Lovecraftian monster. These types of ceremonies are common today and probably were even in the 30s due to people reviving the ancient pagan beliefs. Thus a cult pretending to perform an ancient pagan ritual would be viewed as more of a curiosity than a real threat. The PCs themselves would be tourists who've come to watch one of these ceremonies while on their way to some other location or adventure. Neither they nor anybody else takes it seriously until later that night when several people are horribly mutilated. It's up to the PCs to figure out what's happening and destroy the monster. But that's only the beginning. The cult is searching for other megaliths they know should exist from studying the ley lines and where they intersect. The more of these monuments they control, the more powerful the monsters they summon. It's up to the PCs to follow the cult around the world and combat it at every location, hoping to prevent the cult from summoning a creature strong enough to destroy the world.