While you're visiting Rarotonga, getting onto—and into—Muri Lagoon is a must. Take a lagoon cruise in a glass-bottom boat that skims across the shallow aquamarine waters. When you stop for snorkeling, you'll see brilliantly colored reef fish and giant clams; your guide might point out a moray eel. Then you'll proceed to a white-sand beach on a private motu (islet) to continue your Cook Islands immersion with a lunch of fish barbecued over an open fire, accompanied by traditional music. Typically, an intrepid islander will show how to climb a palm tree to pick coconuts, and another will demonstrate creative ways to tie a pareu (sarong).