This mod adds stuctures based on real life places. They're somewhat rare to find just because it would be annoying if they spawned all over the place. You might have more luck finding something in a desert or in plains.
I tried making the chests have items, but it didn't work. What I might do is place blocks instead.
The Bellagio - Spawns on sand and has beds on the second floor. Useful for setting a spawn point if you get lost in a desert
The Alamo - it looks like a little house
The IDS Center - it's just a random place with a jukebox
Casa Loma - It looks like a little castle with a red roof
Times Square One - Its looks like a tower
Time Warner Center - it has two blue towers on it
Grand Central Station - It looks like a small building with a doors on all sides
Westminster Abbey - it's a just a random church
Citadel of Saladin - It's just a random place that spawns in deserts
Himeji Castle - A japanese castle, probably one of the biggest of the builds