#1 Borussia Dortmund - The Westfalenstadion

The Westfalenstadion (often called as Signal Iduna Park for commercial reasons) is one of the most famous stadiums for its electrifying atmosphere. It has a seat capacity of 81,365 and is the seventh-largest stadium in Europe.
The club holds the record for average fan attendance (2011–12 season) with an average attendance of 80,588 per game.
The fans of Borussia Dortmund are known for their loyalty. After the clubs form dipped in 2014/15, one would think the fans visit to the stadium will go down too. They finished 18 points behind Bayern Munich last season. However, Dortmund trounced all other European giants in attendance as they boasted an average attendance of 79,653 last year.
This year, the number slightly increased to 79,886 as the club which is nick-named as die Schwarzgelben is leading the Bundesliga title race this season.