This is a visual comparison created by Redditor movielover278 of the largest known class of Star Destroyer compared to the size of Manhattan. For reference, Manhattan is 13.4 miles (21.6 km) long and 2.3 miles (3.7 km) at its widest. So that is a pretty big ship. You think it has a shopping mall on board? How else are all those Storm Troopers supposed to spend their paychecks? They need to be able to buy gifts to send home to their wives and kids. Or is Amazon canon in the Star Wars universe? I hope J.J. Abrams answers these questions in the next movie. Also, have you ever stopped to consider maybe J.J. stands for Jar Jar?! Did I just blow your mind? No? Did I just blow bubbles in my chocolate milk? Yes, and now there's milk in my keyboard again.
Thanks to Stephanie A, who is going to build a Super DUPER Star Destroyer that is so powerful it can even destroy black holes. Holy smokes! Whatever you do don't point that thing at me.