A crowd of people stand in street in front of a series of white tents.
A crowd of people stand in the street.
A crowd of people stand in the street is literally the same as the beginning of the first sentence with only a "the" inserted: A crowd of people stand in street in front of a series of white tents.
There is a crowd in the street.
"A crowd of people stand in the street" is the same without the description of what the people are next to.