There are currently 150 temples of the Church of Jesus Christ of Latter-day Saints in the world. Temples are different buildings from the regular church building where members of the church worship on Sundays. There isn't a temple in Nathan's mission, but there is one close by in Redlands, California, just north of his mission boundaries.
Every mission is different with regards to attending the temple, but Nathan's mission president allows the missionaries to go every three months. His preparation day was moved from Monday to Wednesday this week so he and other missionaries could attend the temple. Here is a picture of this special day:
And, one last picture from this week because there wasn't a lot of time for him to email.... Nathan sent this picture of a street sign which reads YOLO - "You Only Leave Once."