Deal Castle in Dover

You're standing at Deal Castle, on the Kent coast. Take a look at its shape. From above, this fort looks like a flower: a round tower in the middle, six semicircular bastions around it, and another six around those. Henry VIII had it built in 1539 and 1540. He'd just broken with the Pope to end his marriage, and France and the Holy Roman Empire teamed up against him. An invasion looked certain.