How to describe crowded tourist attractions?

This situation can be described by the following idioms:

1, a sea of people: a sea of people, a lot of people gathered.

2, rubbing shoulders: shoulders touch shoulders, feet touch feet, describing how crowded people are.

3. Empty alley: An empty alley means that thousands of people flock to a place (to attend a grand ceremony or watch a lively activity), leaving an empty alley empty.

4, shoulder to shoulder contact: shoulders together, footprints connected. Many people are still one after another.

5, sleeves rolled into a cloud: many people also indicate a prosperous scene.