Cambridge Dictionary gives this definition about "block"
the distance along a street from where one road crosses it to the place where the next road crosses it, or one part of a street like this, especially in a town or city
Consider the area pointed out by the red rectangle shown below
From the left to the right, the first part "the distance along a street" becomes "the distance along Independence Avenue"; then second part "where one road crosses it to the place where ..." becomes
"where 4th st SW crosses it to the place where ..."
question#1: Is the area pointed out by the red rectangle called a block?
question#2: Does "it" here refer to Independence Avenue?
question#3: Does "the place" here refer to the block?
question#4: I guess "one part of a street like this" means some other style/shape of block, What does that refer to?