Fig. 12. Bella Vista (Bolivia). Left: selected profiles across archaeological structures. Right: Magnetogram of a typical ring ditch of Pre-Hispanic cultures. The northern and southern part of the ring ditch is clearly visible while the eastern and western part of the ring is nearly fading out. Magnetometer survey with Smartmag SM4G-Special caesium-magnetometer, sensitivity ± 10 Picotesla, variometer (duo-sensor) configuration, 40 × 40 m grid, spatial resolution 12.5 × 50 cm, interpolated to 25 × 25 cm, intensity of total Earth's magnetic field at the site: 24.000 ± 20 nT, date 8/2010, angle of dip -5°, grey shade plot in 256 greyscales from positive (black) to white (negative)