Romanesque architecture has basic characteristics. I quote: "Romanesque architecture is an architectural style of Medieval Europe, characterized by semi-circular arches, and evolving into the Gothic style, characterised by pointed arches, beginning in the 12th century."
Most buildings of Romanesque architecture are massive, with thick walls, high ceilings, sturdy pillars, massive vaults, subterranean passages, and decorative arches.
A religious theme usually pervades the building. If you look carefully at the tiny figures and sculptures, you will notice that many of them are religious in nature and are engaged in some sort of symbolic pose or ritual. Many of the builders of these buildings were paganistic and believed such additions to their buildings actually bestowed certain powers upon them. Many of them just wanted to leave a message.
Because they are so solid and well-built, we have many classic examples throughout most of Europe. In fact, some buildings are so well preserved they are absolute masterpieces! To the art world, they are priceless!