Spain's famous, and extremely controversial, Running of the Bulls festival occurs every year over a 9-day stretch (July 6-14). More than a million tourists visit Pamplona during this time, with a little less than 200,000 residents living there full time. So you can imagine how crowded it gets! All tourists that are there are strictly there for one reason, to see the bulls. The bull run occurs every morning at 8 am and the bull fighting is every night at 6:30. Between those two events, there is not much going on. So travelers do what they do best: conjugate around the cheap alcohol. The cobblestoned streets are lively with fellow travelers greeting each other and swapping stories about that mornings run.
Some tips if you plan on going:
1) Don't miss your train stop. Pamplona in Basque is "Iruna". If you miss your train stop, the next stop is like 1.5-2 hours away. I did this. I'm probably the only tourist in the history of the bull run that missed the stop, but hey, now you know.
2) If you plan to run, spend your first night there talking to people that have done it before. Get a lot of tips and listen to all of them. You most likely want to start somewhere in the middle of the 800 meter dash, and make sure you are not all the way against the wall, but not completely in the middle (unless you're trying to be a daredevil). You don't only have to look out for the bulls, but you primarily have to watch out for other people! There is a lot of shoving. A lot of elbows. And possibly a lot of getting stepped on.
3) Also helpful is finding the bullpen gates and tracking the route so you're completely prepared! Most likely you won't run the entire thing, especially if you've never done it before. But if you do have high goals, it's important to know the layout. Especially of "dead man's curve"!
4) Don't take cameras or anything with you for the run; they will kick you out. You can strap a GoPro on top of your head and you can also stick your phone in your pocket, but I saw multiple people lose their phones because of that, so I wouldn't recommend it.
5) If you just plan on watching, you have to get there EXTREMELY early. If you want to see anything at all you should be there at minimum an hour in advance, but probably even 6:30am would be safe. There are barriers that you can sit on, but once people are sitting on those, there really isn't much space left to see anything.
6) There are also ways to rent balconies from locals, which I would say is the best way to watch the run. The run is only about 8 seconds, so you really need a good spot to see it! You can search online and find someone to rent from, but make sure you do it far ahead of time.
7) And talking about far ahead of time, with a million tourists coming in just for these events, hotels sell out quite early. So book as soon as you decide to go!
8) Buy the three liters of sangria for 5 euro. It's cheap, it's good, it's fun.
9) If you go to a bullfight and happen to sit on the top deck between sections 13-16(ish), don't wear nice clothes. This is the rowdy section, similar to the student section of an American football game. You will be covered in sangria afterwards!