On day 3 of his adventure in France with Cheryl and Roger, Ike headed into Brittany, to the town of Fougères with its magnificent castle and gothic church of St Leonard, which dates from the 16th century. The castle itself was first built in stone in the 12th century after the English burnt the pre-existing wooden one to the ground, Ike spent the whole day learning about its history as the largest medieval fortress in Europe and the wars between England and France. You can learn more about this here.
The site for castle construction was chosen for good defensive reasons. As you can tell from the photographs, the castle is set higher than the surrounding low lying land. This meant that unwelcome visitors could not surprise the fortifications as their impending arrival could be seen when they were still some hours away. The Château de Fougères is also protected by being on the inside bend of a meander of the River Nançon.