Noise cancelling headphones can block out the audio but with people just moving around all day the peripheral vision picks up a lot.
Stepping out into the front hallway (but still within range of the wifi) and sitting crosslegged on the floor outside can sometimes work.
There's also underneath your workspace, George Costanza-style. Be sure your coworkers are aware in advance, why, and ok with it, as some might get the wrong idea of why you're down there.
It's not for people to sit there all day every day and take up residence in this area, it's for when you need to do something that requires concentration and those around are doing the same i.e. no phone calls, no conversations, no eating snacks, like a library really. If you need to do any of those things, you find yourself a spot in the rest of the office.
Failing that, it's either get used to it, try and find the quietest spot you can, or ask if you can work from home/elsewhere.