Why did they made it 3 hours

Rating: Null/10 (12 August 2019)

I was waiting for this movie for so long and when I got that I couldn't wait to watch it when I started playing the movie it showed 3 hours I was surprised and then the dialogues I thought that I might have gotten the wrong one the one with no editing. I was 3 hours movie with 20 minutes of of that avengers which I was expecting. so disappointed how they ruined it for me