Occurred during early evening hours. LARGE UFO (witnessed by many in neighborhood) hovered over open field at end of housing project. Loud, "hummimg" sound emitted; no other noise; no white lights but, edge of craft encircled by blue..turning to green ...to red lights. No one in crowd felt threatened..no panic (I couldn't beleive it!), just in awe..everyone almost frozen. It was directly over our heads in a wide-open farm field. Do not remember how long it was there...I ran home to tell my parents ( I was 7 yrs. old at the time). Did not see craft "appear" or "disappear"...it was so fast.