In the 44th century, around the year 4380, Comet Hale-Bopp is expected to return to the inner solar system. It last dominated the skies of Earth in 1996-1997.
In the 49th century, The Great Comet of 1811 is expected to return to the inner solar system. According to calculations made at the time, the comet should return around the year 4876.
Snowdonia is particularly rich in its prehistoric archaeological sites, dating from the initial Neolithic colonisation of the area in the 4th millennium BC to the pre Roman era corresponding to the last half of the first millennium BC.
There are equally interesting sites belonging to the period of Roman occupation in the first half of the first millenniumAD, as well as to the later early Christian and Medieval periods when Wales was first identified as a geographical and cultural entity from the 5th century AD onwards.
Finally, the people of Snowdonia entered into the Industrial Revolution of the late 17th to early 19th centuries AD when its natural resources were exploited, leaving behind a number of important industrial monuments as well as establishing an industrial settlement pattern of villages and towns within an area renowned for the beauty of its landscape.