MRAUK-U, Myanmar — It was dusk in a corner of Myanmar recently shaken by some of the bloodiest sectarian violence in a generation, and a dozen Canadian tourists climbed to the top of a grassy hill, cameras ready to capture the sweeping view.

Moss-covered pagodas rose from foggy hilltops all along the horizon, their bell-shaped silhouettes dark against the blue sky. Birds flitted through lush treetops. A small throng of children played on a dirt road nearby.

From here, it was hard to tell anything was wrong....