text: Standing isolated surrounded by the vast, golden north Saudi Arabian desert is a bizarre single rock castle, which has been lying undisturbed for centuries. Qasr al-Farid or 'The Lonely Castle' has a sad tale, standing incomplete and abandoned, looking out of place in the vast, barren landscape. Believed to be constructed in the first century A.D. and situated on one of the most important ancient trade routes, linking the north and south of the Arabian peninsula, the mysterious monument was never finished. Scroll down for video . Now a UNESCO World Heritage Site, the ancient remains of Qasr al-Farid - a rock-cut tomb and part of an ancient Nabatean settlement - stands amidst imposing cliffs and striking rocky outcrop . The Nabatean Tomb in Madain Saleh is located in the northwestern region of the Arabian peninsula, in the middle of a vast desert landscape . Size matters! The striking structure is the largest of the 131 tombs in the area, hinting it was intended for someone of great power . Despite its misleading name, the fascinating four-storey monument was actually used as a tomb. It's intricate carving borrows decorative elements from Egyptian, Hellenistic, and Assyrian architecture. The tomb is the largest of 131 monumental tombs, which were carved straight into rock in the city of Mada'in Saleh during the pinnacle of Nabatean era. And it is famous for standing completely alone. Size would have been indicative of the person's social status and wealth, hinting it was intended for someone of power. It is remarkable how The Lonely Castle has remained so preserved against the elements for over 1,900 years and this can be attributed to the dry climate. Situated on a pre-Islamic archaeological site located in Al-Ula, is located on one of the major trading sites, which linked the south of the Arabian peninsula to the north. Unesco declared the magnificent historic collection Saudi Arabia's first World Heritage site in 2008. Nabataeans constructed their massive stone buildings mainly from single pieces of sandstone, and carved from the top down . If the smooth stone reminds you of the iconic carved site of Petra in Jordan, it should come as no surprise to learn they are linked. Petra was the capital of the Nabataean kingdom and features a 250-foot-high  sandstone slot canyon known as the Siq. Until 1812, the site was unknown to the western world until it was introduced by explorer Johann Ludwig Burckhardt. While Petra was the capital of the Nabatean kingdom, Mada'in Saleh was its second city, explaining why the unusual carved rock architecture is so similar. Petra in Jordan was the capital of the Nabatean Kingdom. It displays similar architecture design to Qasr al-Farid, being carved out of a single stone body. It is sometimes known as the Rose City due to the color of the stone . Impressive collection! Another Saudi Arabian Nabatean tomb, Qasr al-Bint, has been perfectly preserved in the dry climate. UNESCO declared the historic series of tombs Saudi Arabia's first World Heritage site in 2008 .
target: Qasr al-Farid or 'The Lonely Castle' has been standing strong since the first century AD .
  The single-rock tomb is incomplete and abandoned, but fascinatingly reveals structures were carved from top down .
  The striking castle is one of 131 tombs from the Nabatean Kingdom, located in the Al-Ula sector .