Where in Number City?

How well do you know Number City? We've used a spotlight to take some pictures of parts of the city — can you guess where they were taken?

In Number City, each number is represented by boxes corresponding to its prime factors. For each image, we want to know which number the box marked with a question mark belongs to.

For example, 15 = 3 × 5, which is represented in Number City by a box for the 3 and a box for the 5 — and if either of them has the question mark on it, the answer for the question is "15".