Complex sentence: Work started on the current lighthouse in 1855, and it was completed and first lit on November 15,1860, with a final cost of $300,000 that made it the most expensive light house that was ever constructed in the United States.
Split into simpler sentences: Work started on the current lighthouse in 1855, and it was completed and first lit on November 15,1860. With a final cost of $300,000, it was the most expensive light house that was ever constructed in the United States.