Many volumes have been written by archeologists and historians about the ancient historic sites of Greece and Athens in particular. Researchers from universities all over the world spend much of their time studying various aspects of ancient Greek civilization, based on the many valuable finds carefully guarded in museums. Ancient Greeks aimed at harmony between all aspects of life, religion, art, sports, entertainment, knowledge and always honored their heroes. The Acropolis, probably the most famous of historic sites in Greece and worldwide, is a symbol in itself and an outstanding landmark of the city. The temple of Olympian Zeus, with the large surrounding area and the more recent Romans Emperor Hadrian's Arch on one side, is a tribute to the father of all the ancient gods, Zeus himself. The ancient Agora played an important role in everyday life in ancient Athens. Kerameikos cemetery still maintains an aura of peace and stillness in the midst of the bustling city. Just an hours drive from the center, the Temple of Poseidon at Sounion ancient god of the sea, is a must day trip. Vravrona with the temple dedicated to the goddess Artemis is an enchanting place to visit, Amphiareion sanctuary at Oropos maintains the healing energy for which it was famous in ancient times, at Ancient Nemea, not far from Corinth, the ancient games have been revived, attracting visitors from many countries, the historical church of the Holy Sepulchre in Plaka is the receiving point for the Holy Light of the Resurrection from Jerusalem every Easter.