1) Pyramid of the Inscriptions, Palenque Mexico (Mayan).  This beautifully balanced pyramid with the jungle-covered hills in the background is my personal favorite. 

2) Cheops Pyramid, Giza, Egypt (Old Kingdom, Egyptian).  The size, dimensions and desert background, combined with the age makes this #2.

3) Temple I, Tikal, Guatemala (Mayan).  As with all five temples in Tikal, this pyramid is almost too steep to climb.  The flat jungle expanse spreads out like an ocean from the five temples.

4) Step Pyramid, Memphis, Egypt (Old Kingdom, Egyptian).  The oldest pyramid in Egypt.  It looks just like the Mesoamerican pyramids.

5) Pyramid of the Sun, Teotihuacan, Mexico (Teotihuacan).  Massive, and perfectly aligned with the sun and stars on the vernal equinox, the history of this place is largely unknown.

6) El Castillo Pyramido, Tulum, Mexico (Mayan).  Small and beautiful, on the shores of the Mexican Caribbean.

7) Pyramid of the Morning Star, Tula, Mexico (Toltec).  What makes this pyramid so special are the carved stone "Atlantes" that once help up a massive roof to a temple.

8) Pyramid of Tzintzuntzan, Michoacan, Mexico (Purepechas).  This pyramid is not square, trangular, or round, but is long, like a snake.  Perhaps the strangest pyramid I've ever seen.

9) Cuicuilco, Mexico City, Mexico (Cuicuiltecas).  This one is round.  It's the second strangest pyramid I've seen.  It was burried by a volcanic flow from the Xitle Volcano which sits in the middle of the University Campus in Mexico City.

10) Tepozeco Pyramid, Tepoztlan, Mexico. (Mexica).  Built high up on steep cliffs above the town of Tepoztlan, it has been a pilgrimage site for centuries.