A ruined arch sitting alone on a blasted landscape. The benign remains of an ancient civilization or something more sinister? What will befall those two curious travelers who have taken shelter in the dark shadows cast by the grim edifice? Will they dare to make camp beneath the crumbling stone structure as growing storm and darkness descends upon them? What lies beneath mounded earth surrounding the ruin? Why does nothing grow? It's not a bad start for an adventure; and you don't even need to go underground.