One of the first castles erected by the victorious William the Conqueror, in 1068, to keep his new kingdom in line, Lincoln Castle offers awesome views over the city and miles of surrounding countryside. A major 2015-completed restoration program opened up the entire castle walls and gave the 1215 Magna Carta (one of only four copies) a swanky, subterranean new home. One-hour guided tours, included in the castle admission, depart from the eastern gate; check the blackboard for times.
Videos and exhibits explain the document's significance, while the surprisingly bright Victorian prison houses a unique 'separate-system' chapel and displays a Saxon sarcophagous found during the restoration. Watch for concerts in summer. The grounds make an idyllic picnic spot in fine weather.