User blog:Manco.45/Strange arch in mexico

I stumbled across this arch yesterday while on the main road through mexico, as you can see chuparossa and barranca are in the background. It appeared just after the mission 'Cowards die many times' but it had disappeared when I returned several missions later, this is my fourth playthrough of the single player campaign and I have never seen it before. It's a simple wooden arch, just like those in settlements but it has black and white flags hanging below, which leads me to think that it might be some sort of race. It's probably just a spawning glitch or something but I cant help wondering if it's some sort of easter egg, if any of you guys have seen this arch before in game or in any western movies let me know please.