At the tip of the Great Northern Peninsula of the island of Newfoundland, the remains of an 11th-century Viking settlement are evidence of the first European presence in North America. The excavated remains of wood-framed peat-turf buildings are similar to those found in Norse Greenland and Iceland.
Dating to around the year 1000 (carbon dating estimate 990-1050 CE), L'Anse aux Meadows is the only site widely accepted as evidence of pre-Columbian trans-oceanic contact. It is notable for its possible connection with the attempted colony of Vinland established by Leif Erikson around the same period or, more broadly, with Norse exploration of the Americas.
Today the area mostly consists of open, grassy lands; but 1000 years ago, there were forests which were beneficial in boat-building, house-building and for iron extraction. The remains of eight buildings were located. They are believed to have been constructed of sod placed over a wooden frame. Based on associated artifacts, the buildings were variously identified as dwellings or workshops.
L'Anse aux Meadows was named a World Heritage site by UNESCO in 1978.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.