Stonehenge, Britain's 5,000-year-old wonder, draws 850,000 visitors a year. But its ancient ambience is sullied by its forlorn amenities—a parking lot that's way too small and a shabby visitor center—and noise from nearby highways. Plans for a $1.2 billion upgrade were introduced about seven years ago. They include a large, modern tourist center about 2 miles away, linked to the stones by a footpath and a train service. One nearby road would be rerouted, another diverted down a 1.3-mile-long tunnel. Unhappy residents near the planned center fought the proposal. Local authorities finally OK'd it last year—but only if the tunnel is built. Now transportation officials, balking at spending $1 billion on the highway portion of the plan, are threatening to drop the tunnel. That would require starting the planning process anew.