Some of Mazatlán's most beloved sites are centered in the Centro Histórico, or Old Mazatlán (sites like the Basilica of the Immaculate Conception). So you won't need to make a special effort to enjoy this part of town, but you can rest assured that you'll spend plenty of time there. And if you only have one day in the area, this is where travelers suggest you come. 

And you should come hungry. Recent TripAdvisor travelers litter their endorsements with food recommendations; you'll have the option for taco de cabeza (tacos prepared from the head of a cow) or papas locos (giant baked potatoes) from a street side vendor, or delicious shrimp tacos at a Plaza Machado café. Walk off your meal with a tour of the Teatro Angela Peralta opera house or a stroll along the Malecón.