Where did concentric castles come from?

What are the physical characteristics of the cn tower? How many state are west of Mississippi river? How did the egyptians take advantage of nile yearly spring flooding? Which plants might be found in a mesozoic forest? A stone that is initially at rest is dropped from the top of a building it falls for 5.0s before hitting the ground how tall is the building? Who were the first Europeans in great lakes information? Is Rockefeller Center open on Christmas day? Who was the one leged lady climb Everest? What was Long Beach CA original name? What is the outer layer of the statue of liberty made of? Why do you have castles? Which state shares the Niagara Falls with Canada? This precipitation gathers into and that flow down to the lakes and oceans? What are the seasonal changes in lake okeechobee? What is the medium in ocean waves? Where is yacht bandido kept at Is it in Huntington Harbor or Newport Beach Ca? Where is San Carlos Borromeo Mission Located? Why tropical plant species should be more specialized in terms of pollinator attraction compared to temperate species? Is large lake and large basin eroded by plucking and abrasion erosion or deposition? When did knotts berry farm open?