Hilary Duff and Mike Comrie took a walk around Manhattan with their son, Luca, yesterday. The couple's almost 4-month-old baby is visiting NYC for the first time, but he's already made multiple other trips. Hilary brought Luca to Mexico in June and earlier this month they checked out Napa. While packing for the East Coast getaway, Hilary tweeted, "This baby is world traveling!" It's been an exciting Summer for the Duff-Comrie family and they still have more fun in store. In August, Mike and Hilary will celebrate their two-year wedding anniversary. They tied the knot in Santa Barbara back in 2010.