Josh Denny two-steps into Tucson, Ariz. in search of the Southwest's most monumental meals. Boca Tacos y Tequila serves up the Titanic Taco Dog, a five-pound taco piled high with pinto beans, cactus salsa and bacon-wrapped hot dogs. Mega meat and searing heat come together at Lindy's on 4th, where a six-pound burger named The Burn Out gets topped with jalapenos and pepper Jack cheese, then smothered in a sauce made with the hottest chili on the planet. Finally, the Stray Dogs Grill rolls out a sixteen-inch-wide, chocolate-filled glazed doughnut called The B.F.D.