One of Minnesota’s biggest attractions is about to get larger. Construction will start this fall on an addition to the Mall of America’s north side that will include up to 50 new shops, a new food court, a new atrium, an office tower, and another luxury hotel. An NHL-sized skating rink and world class water park are on the drawing board, too. It’s part of a $2.5-billion expansion aided by a $250-million tax break approved by the Legislature this spring. When the expansion runs its course the mall will have nearly doubled in size. The megamall attracts 42-million visitors annually, and the expansion is expected to lure around 20-million more.