Nearly 3 miles long and 300 feet wide, gold-sand Papohaku Beach is one of the biggest in Hawaii (17-mile-long Polihale Beach on Kauai is the biggest). It's great for walking, beachcombing, picnics, and sunset watching year-round. The big surf and rip tides make swimming risky except in summer, when the waters are calmer. Go early in the day when the tropic sun is less fierce and the winds are calm. The beach is so big that you may never see another soul except at sunset, when a few people gather on the shore in hopes of spotting the elusive green flash, a natural wonder that takes place when the horizon is cloud-free.