Just as a visit to Stromboli should come with a side trip to Etna, visitors to Congo's Nyamulagira should take in its neighbor, Nyiragongo volcano (pictured).
A perfect cone towering 11,384 feet (3,470 meters) above equatorial Africa, Nyiragongo houses a lava lake in its crater, accessible to intrepid (and fit) visitors via a challenging trek (guides and armed guards required).
Treks set off from nearby Goma—a city of 500,000 dangerously close to the volcano. Nyiragongo has unusually liquid lava that can rush down the slope at startling speeds when the lava lake drains.
"The high speeds [at which] the lavas can flow make this a dangerous and unpredictable killer," volcanologist Leat said.
The treks, which include camping, extend through the night, when the lava becomes a pageant of reds and yellows, according to blogger John Tull.
"The sight is mesmerising," Tull wrote on his blog, Kiwi in Kigali. While "gas plumes waft around, obscuring one moment and revealing the next, the lava lake seethes with implied forces that roar and crackle below. ... The thin surface crust is fractured and re-fractured constantly, like the glaze on a crème caramel."