Dan Snow boards a yacht on the English channel to get a sense of the naval battle, revealing how tensions between England and Spain were fuelled by religion, piracy and Elizabeth I's rejection of King Philip II of Spain as a suitor 30 years earlier, and how a missed opportunity could have resulted in disaster.

Dan relives the fierce battles at sea and we go behind the scenes in the royal court of Elizabeth as the Spanish fleet prepares for full-on invasion.

Newly discovered documents reveal a remarkable web of misunderstandings that stopped the Spanish from invading, and show how the English victory forged the reputation of Elizabeth.