Monaghan returned to Ann Arbor, Michigan, in 1959, and enrolled in the University of Michigan, intending to become an architect. While still a student, he and his brother James borrowed $900 to purchase a small pizza store called DomiNick's in Ypsilanti, Michigan. "I started out in architecture school, and got into the pizza business to pay my way through school," he has said. "The pizza business was losing so much money I never got back into architecture." This business would, after a lawsuit from Domino Sugar, grow into Domino's Pizza. Tom, after opening a further three stores, traded his brother James a Volkswagen Beetle for his half of the business. Monaghan dropped sub sandwiches from the menu and focused on delivery to college campuses, inventing a new insulated pizza box to improve delivery. The new box, unlike its chipboard predecessors, could be stacked without crushing the pizzas inside, permitting more pizzas per trip, and keeping them warm until they arrived. As Monaghan spread his model to other college towns through a tightly-controlled franchising system, by the mid-1980s there were nearly three new Domino's franchises opening every day.