huge crowds of people 人山人海；人头挤挤

【例句】
We see heavy traffic on the street, huge crowds of people.
我们看到街上车水马龙，人山人海。

I walked along the Huaihai Rd. until I came to Xujiahui with its movie theatres, neon lights, and huge crowds of people.
我沿着淮海路一直走到徐家汇，徐家汇到处是电影院，霓虹灯和人山人海。