What do the pyramid and eye on the back of our one-dollar bill mean? Are they anti-Christian?
The symbols to which you refer are the reverse side of the Great Seal of the United States: the triangle and eye atop an unfinished pyramid with the words Annuit Coeptis above them and the date 1776 in Roman numerals below with the words Novus Ordo Seclorum. We are more accustomed to seeing the front side of the seal with the American eagle clutching 13 arrows in its talons.
The Department of State, keeper of the seal, says the pyramid symbolizes strength and durability. The 13 layers of stone represent the original states. The fact that the pyramid is unfinished means the United States is always growing, building, and improving.
In Christian symbols a triangle represents the divine Trinity and an eye the all-seeing eye of God. It suggests the importance of divine guidance. Annuit Coeptis can be translated "He [God] has favored our undertakings" and Novus Ordo Seclorum, "A new order of the ages," meaning the new American era.
There is nothing inherently anti-Christian in any of these symbols.