Leaving from a dock by the Maritime Aquarium, ferries take trips during the summer to Sheffield Island Lighthouse (Seaport Dock, Norwalk, 203/838-9444, www.seaport.org [1], May–Sept., in Norwalk, schedules set annually, $20 adults, $$12 children 4–12, $5 children 3 and under), a handsome stone beacon that was built in 1868. Now retired, the house harbors a lighthouse museum; nature trails loop around the three-acre island.
On the other side of the highway, the Lockwood-Mathews Mansion Museum (295 West Ave., Norwalk, 203/838-9799, www.lockwoodmathewsmansion.org [2], tours hourly, noon–4 p.m. Wed.–Sun., free) is located in a Second Empire château-like home owned by wealthy merchant Charles D. Mathews. The entire home is filled with knock-your-socks-off furniture and artwork, including an impressive painted ceiling.
Links:
[1] http://www.seaport.org
[2] http://www.lockwoodmathewsmansion.org