The Jardin Exotique de Monaco is a botanical garden located on a cliffside in Monaco. The succulent plants were brought back from Mexico in the late 1860s. By 1895, Augustin Gastaud, who served as the Chief Gardener of the State Gardens of Monaco, grew the succulents in the Jardin St Martin.
Albert I, Prince of Monaco acquired a piece of land in Les Moneghetti in 1912. He commissioned Louis Notari, the Chief Engineer of Monaco, to build a new garden with footbridges. During the construction, Notari found a grotto underneath in 1916.
The grotto was opened to the public in 1950, but it may only be visited with specialized guides. Evidence of prehistoric human inhabitants has been found in the cave. There is a museum of Prehistoric Anthropology within the Exotic Garden displaying many of those prehistoric remains. It was founded by Prince Albert I in 1902.
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.