The Tomb of the Eagles, or Isbister Chambered Cairn, is a Neolithic chambered tomb. First explored by Ronald Simison, a farmer, when digging flagstones in 1958, he conducted his own excavations at the site in 1976. Alerted by Simison, archaeologist John Hedges then mounted a full study, prepared a technical report and wrote a popular book that cemented the tomb's name.
16,000 human bones were found at the site, as well as 725 from birds. These were identified as predominantly belonging to the white-tailed sea eagle (Haliaeetus albicilla) and represented between 8 and 20 individuals. These were originally interpreted as a foundation deposit, however this interpretation has been challenged by new dating techniques. These reveal that the eagles died c. 2450–2050 BC, up to 1,000 years after the building of the tomb. This confirms growing evidence from other sites that the neolithic tombs of Orkney remained in use for many generations.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.