Donuts over Buenos Aires /ArgentinaMy daughter (6) and Me(38) were sitting in the backyard. Coming from east side 2 objects and turning over our location to northwest. The sky was very clear, no clouds, no fog or mist. The night was dark, with no moonshine. Temperature 20 deg. Celsius.The objects seemed like a flat donut or a washer. No light emission, only the reflection of the streetlights over their surface. A little movement (oscillation) in the horizontal plane. Very sharp edges. The center of the donut was dark like the rest of the sky. No noises, no electrical disturbances. The 2 objects were identical, approx.2 times the size of the moon It is not easy to estimate the altitude, but it must be at the cloud level, because their size was constant. They appeared and disappeared at 30 deg. over the horizon, because the reflection over their surface was to low at this distance. The best view was over our location.I know to identify objects at night, and this was to fast (5 seconds)at medium altitude , very sharp edges . It was not a cloud, birds, balloon, plane, reflections of car lights.I used to work with lasers, and pointing them to a cloud, you never get a sharp image like this was .From this day on I was trying to find a similar description of another event, without success.((NUFORC Note: Source of report indicates that date of the event is approximate. PD))