The Christianity presence in the Holy Land is reflected by the many, churches which commemorate episodes involving Jesus and the other Christianity founders. The first churches were built in the 4 th century, including the two most important churches in the Holy Land, the Church of the Holy Sepulchre and the Church of the Nativity, both constructed by Helena. In the Byzantine period, churches were built throughout the Holy Land, from the Nabatean cities in the Negev in the south to Nazareth and the Sea of Galilee in the north. In the Crusaders’ time, new churches were built and many others from the Byzantine period were made anew. As part of an agreement between the Ottoman Empire and the European empires in the second half of the 19 th century, a new wave of church construction took place, many of them in Jerusalem. Today, you can find ruined churches in large numbers, mainly from the Byzantine period, almost everywhere in the country. The most accessible ruined churches are those in the Nabatean cities, Jerusalem , Emmaus Nicopolis, Beit Guvrin, Caesarea , and Kursi. Additional important Christian historical sites are in Qumran, the Baptismal Site of Jesus Christ on the Jordan River and the Garden Tomb, Via Dolorosa, and the Mount of Olives in Jerusalem. Functional churches from all denominations of Christianity can be found throughout the country. The main clusters of churches are in Jerusalem, Ein Kerem, Jaffa, Haifa, Nazareth, and Kafr Kanna, and around the Sea of Galilee. There are monasteries in the Judean Desert and in all other Christian clusters in Israel. For hikers, there is a signed three-day hiking trail (The Jesus Trail) from Nazareth to Tabgha on the north-western shore of the Sea of Galilee.