In this work we apply generalized A. Sparavigna method (use of freely available softwares (programs), e.g. http://www.sollumis.com/, http://suncalc.net/#/44.557,22.0265,13/2014.12.29/09:22, http://universimmedia.pagesperso-orange.fr/geo/loc.htm, http
://www.spectralcalc.com/solar_calculator/solar_position.php and http://www.fourmilab.ch/cgi-bin/Yourhorizon) for analysis of possible astronomical characteristics of three remarkable Giza, i.e. Cheops, Chephren and Mikerin pyramids. Concretely, we use mentioned programs for determination of the Giza plateau longitude and latitude, moments of the sunrise and sunset for any day at the Giza plateau, and, simulation of the sky horizon above Giza plateau in any moment of any day, respectively. In this way we obtain a series of the figures which unambiguously imply the following original results. Any of three remarkable Giza pyramids (Cheops, Chephren and Mikerin) holds only one characteristic edge between apex and north-west vertex of the base so that sunrise direction overlap almost exactly this edge during 28. October. (There is a small declination of the overlap date by Chephren pyramid by which overlap date is approximately 23. or 24. October.) Simultaneously, in the sunset moment for the same day, Taurus constellation (corresponding to holly bull in ancient Egypt mythology) appears at a point at the very eastern boundary of the sky horizon.
In this work we consider some old hypotheses according to which remarkable mesolithic village Lepenski Vir (9500 -- 5500 BC) at the right (nearly west) Danube riverside in the Iron gate in Serbia was an ancient (one of the oldest) Sun observatory. We
use method recently suggested by A. C. Sparavigna, concretely we use freely available software or local Sun radiation direction simulation computer programs. In this way we obtain and discuss pictures of the sunrise in the Lepenski Vir during winter and summer solstice and spring and autumn equinox in relation to position of the mountains, especially Treskavac (Trescovat) and Kukuvija at left (nearly east) Danube riverside (in Romania). While mountain Kukuvija represents really the marker for the Sun in date of the winter solstice, mountain Treskavac, in despite to usual opinions, does not represent a real marker for the Sun in date of the summer solstice. Sun rises behind Treskavac, roughly speaking, between 22.April and 1. May. It corresponds to year period when heliacal rising of the Pleiades constellation occurs, which by many ancient cultures, e.g. Celts of northern Europe, denotes very beginning of the year. All this, in common with some archeological facts (house-shrine No.47 in the Lepenski Vir holds seven signs beside hearth which would correspond to the seven Pleiades stars), opens a possibility that Lepenski Vir was an ancient Pleiades constellation observatory.
