If you're interested in gazing into the cone of a live volcano, Indonesia is the place to go. Some 120 of them dot the country, and several are considered safe. Still, it's best to check conditions before visiting—the country averages about 10 major eruptions per year. Some of our favorite volcanoes are on Java: Tangkuban Prahu (18 mi/29 km north of Bandung, in Western Java) is popular, but it puts out sulfur fumes and smoke.

If you don't care for the smell of sulfur, you may prefer Mount Bromo, near Surabaya in East Java. An all-night tour takes you down to the sand floor of this 9,000-ft/2,750-m crater—at night it glows red (spooky and fabulous). The sunrise is another special time around Bromo, and there are many organized tours to view the volcanoes at daybreak.

One of Java's other big draws, Mount Merapi, threatened to erupt throughout much of mid-2006—killing two people in the process—but has settled down again, for now. Mounts Batur and Agung on Bali are other good choices.