Complex sentence: The mansion of the estate currently houses the Holocaust Museum and Tolerance Center of Nassau County which, as of 2014, is open on Mondays to Fridays from 10:00 am to 4:30 pm, and on Saturdays and Sundays from 12:00 pm to 6:00 pm.
Split into simpler sentences: The mansion of the estate currently houses the museum part of the Holocaust Memorial and Tolerance Center of Nassau County. As of 2014, the museum is open on Mondays to Fridays from 10:00 am to 4:30 pm, and on Saturdays and Sundays from 12:00 pm to 6:00 pm.