Personally I have always thought the Nazca region was simply pictographs and that lines around it were just pictographs that never were completed or were reference lines.
A region that intrigues me a little more in Peru is the Pisco highway. Google Earth 13 degrees 46' 57.56" S, 76 degrees 02' 49.92' W
This road goes for many miles through the desert and has 1-2 m holes spaced evenly along it. I am sure the holes are man-made, but for what purpose? At the terminal end of the road is a grid of holes (see 13 46 16.00 S, 76 09 04.15 W). Maybe some failed public works project?
Also concerning another interesting region:
I live in Tucson, AZ with my wife, but we are originally are from Texas, so we fly back to visit parents a few times a year. Every time we fly the flight pattern takes us over El Paso and west Texas, and I am always amazed at this region: 31 40 56.22 W, 106 05 32.64 W
There is a small town nearby (Aqua Dulce), but these empty subdivision layouts stretch for miles. You don't really get a good appreciation for it from Google Earth due to the fact that some of these regions go into low resolution areas, but in the airplane you can see the immensity of it. Roads formed for Cul-de-Sacs, and crisscrossing for miles, but no buildings of any kind. I wondered why anyone would go through the trouble to map these out, since they are miles from anything.
Finally, some food for thought:
If you go to 48 49 30.80 N, 2 11 54.96 E, you will arrive at a location in France. You will see a military style jet parked in a parking lot. On some Google Earth websites, this is described as being a school building. Perhaps an inspiration for the X-Men movies?