(Source: BYU Archives)
Located on the southwest corner of campus, Allen Hall was BYU's first real dormitory, built in 1938. It was followed closely after by Amanda Knight Hall.
Around 1960, it housed missionaries for the LTM program (a predecessor to the MTC, now located on the opposite corner of BYU's campus). Now, it houses the Office of Public Archaeology, the Museum of Peoples and Cultures, and a few other programs.
You'll notice the tall wooden decoration--I'm assuming that has something to do with the museum. You'll also notice the box covered with a trap--it looks like it's something people use to practice digging up artifacts.
The interior really looks like it is housing a ton of items:
I am a bit concerned for this building. Supposedly, the Museum of People and Cultures will shortly be transferred to the Outdoors Unlimited Building north of campus. What will that mean for this building? I hope that it isn't torn down.