Derry's walls were originally built by the Irish Society between 1613 and 1619. They were built with the intention of protecting the Scottish and English planters that had moved to Ulster as part of the Plantation of Ulster that had been established by James I. It was a direct consequence of the previous settlement being destroyed by Irish chieftain Cahir O'Doherty during O'Doherty's rebellion. As a result of the building of the city's defences by the Irish Society, which was a consortium of livery companies based out of the City of London, the city was officially renamed Londonderry in the 1613 royal charter. This is what has subsequently led to the naming dispute for the city and county of Derry/Londonderry.
The walls are at the centre of the historic city of Derry and within them are a number of Derry's most important landmarks including the Apprentice Boy's Hall and St. Columb's Cathedral.
The walls are about 1 mile in circumference and contain many of the city's most important landmarks. The entire length of the walls is fully accessible on foot. There are seven gates in total, four of which were built at the same time as the walls themselves and three were added later.
References:The Temple of Edfu is one of the best preserved ancient shrines in Egypt. It was built in the Ptolemaic Kingdom between 237 and 57 BC.
Edfu was one of several temples built during the Ptolemaic Kingdom, including the Dendera Temple complex, Esna, the Temple of Kom Ombo, and Philae. Its size reflects the relative prosperity of the time. The present temple initially consisted of a pillared hall, two transverse halls, and a barque sanctuary surrounded by chapels. The building was started during the reign of Ptolemy III Euergetes and completed in 57 BC under Ptolemy XII Auletes. It was built on the site of an earlier, smaller temple also dedicated to Horus, although the previous structure was oriented east–west rather than north–south as in the present site.