Photos: Dave Portnoy bought a $42 million home in Nantucket, complete with an underground tunnel. They're becoming a thing for the rich.

• Dave Portnoy bought a $42 million waterfront home in Nantucket, The Wall Street Journal reported.
• The realtor who sold the home said it had an underground tunnel connecting a studio and guesthouse.
• The Journal previously reported tunnels were becoming more common in luxury homes.

Dave Portnoy bought a record-setting $42 million home in Nantucket, The Wall Street Journal reported, citing people familiar with the deal.