Complex sentence: The next lighthouse was a wooden tower on a masonry foundation, which was demolished during the Crimean War in 1854, and instead, cannons were put on the masonry foundation for firing at ships of the British Royal Navy.
Split into simpler sentences: The next lighthouse was a wooden tower on the masonry foundation. But it was demolished during the Crimean War in 1854, and instead, cannons were put on the masonry foundation for firing at the ships of the British Royal Navy.