Short answers, pulled from the story.
Romanesque architecture emerged in the 11th century and flourished from the 11th to the 12th century. This period began around the year 1066 when William the Conqueror invaded England and introduced a new way of building stone that would define the next two centuries of European history.
Romanesque buildings are characterized by massive quality, thick walls, and round arches that seem to hold up the weight of the heavens. The walls were often of massive thickness, sometimes double shells filled with rubble, to support the heavy loads of barrel vaults and stone roofs.
The most famous pilgrimage destination was Santiago de Compostela in Spain, which claimed the remains of one of the Twelve Apostles and became the most significant pilgrimage site in Europe. Millions of pilgrims traveled the Way of St James on foot, converging at major abbeys like Jumièges, Paris, Vézelay, and Cluny before crossing the Pyrenees.
The monastic system established by the monk Benedict in the 6th century spread from Italy throughout Europe and became the major seats of learning and engines of architectural innovation. The enormous and powerful monastery at Cluny, located in Burgundy, had a lasting effect on the layout of other monasteries and the design of their churches.
The tympanum is the semi-circular area above the door that was typically decorated with the imagery of Christ in Majesty or the Last Judgement. This style of doorway occurred in many places and continued into the Gothic period, but the Romanesque period produced a profusion of sculptural ornamentation that was distinctively its own.
The largest groups of Romanesque survivors are found in areas that were less prosperous in subsequent periods, including parts of southern France, rural Spain, rural Portugal, and rural Italy. Many castles exist, the foundations of which date from the Romanesque period, but most have been substantially altered, and many are in ruins.