Led Zeppelin is a 1970s metal group, although they made many different styles of music, so the actual genre of their music is somewhat ambiguous and could be called many different things.
When Levee Breaks is my favorite song by them due to the heavy drum beat and bluesy, southern guitar that takes me out of this world. It is one of the few songs that I like that is pretty long at seven minutes.
I like long songs if they can maintain my interest like When the Levee Breaks, Paradise City, Stranglehold, Cabo Wabo, Long Time and No More Tears. However, songs like Do You Feel Like We do start off good but get boring after a while because they are too long and repetitive even if they might have a guitar talk box.
Everybody seemed to be making long songs in the 1970s because they were inspired by Led Zeppelin to make at least one epic work each. Some were good and some were terrible. However, it is no doubt that Led Zeppelin was the inspiration for all of these epic works.