The volcano is active, with a small eruption occurring in 2002 and more activity, where the lake changed color and emitted sulfurous rocks and foam, causing it to be closed to tourists in 2004.
The paths are treacherous. In 1997 a French tourist fell and died here.
Ferries make the 20-minute journey from Bali to Ketapang, Java every day. Tours to Kawah Ijen are available from Ketapang itself, or you can take the bus to other nearby towns such as Bondowoso or Banyuwangi.
12. Boseong tea fields, South Korea
Approximately 40% of Korea's tea is produced in the rolling fields of Boseong, which have also provided the backdrop of many South Korean dramas and films.
Yes, green tea-related specialties (fresh green tea ice cream and green tea pork belly) are tasty treats, but the spectacular view of the seemingly endless tea fields is the real reason so many visitors stop by Boseong.
A green tea festival is held every May while in the winter, the fields are decorated with tiny light bulbs.
The best way to get to Boseong is by bus from Seoul. Take an express bus to Gwangju from Seoul Seoul Central City Bus Terminal. From Gwangju Express Bus Terminal, take an intercity bus to Boseong.
13. Fenghuang, China
Every year, armies of young backpackers flock to the ancient town of Fenghuang (which literally means "Phoenix") for its rich Miao and Tujia ethnic culture.
Many also come to pay homage to celebrated Chinese writer Shen Congwen, whose novel "Frontier City" put the 1,300-year-old town in limelight.
Fenghuang maintains its original layout and architecture, with around 200 residential buildings, 20 streets and 10 winding alleys, all of which date as far back as the Ming dynasty.
Admission: RMB 148. Fenghuang is 430 kilometers west of Changsha, the provincial capital of Hunan. Long-distance buses are available four times a day from West Changsha Bus Terminal to Fenghuang Bus Terminal for RMB 130. The journey takes nearly four hours.
14. Borobudur at sunrise, Java, Indonesia
Watching the sun rise over the hundreds of stupas and Buddhas at Borobudur before the public descends in droves to disturb the peace is one of the world's most rarefied experiences.
Guests staying within the village compound are allowed to enter this 9th century monument, hidden beneath volcanic ash for centuries, before opening time.
Black Tomato offers three nights bed and breakfast with private sunrise tour at lavish Amanjiwo, decorated with its own Buddhas and stupas, from $1,195 per person; blacktomato.com
15. Starling murmuration, Brighton Pier, England
They're not exotic, and in the European case they're not even that pretty, but when you have thousands of starlings swooping and wheeling like some kind of hypnotic cloud, they become one of the most mesmerizing sights in natur See a stunning video of the phenomenon on Vimeo.
These murmurations happen just before the birds roost down for the night, and while starling numbers have crashed in the UK, you can still see up to a million birds coming together in these huge swarms in England's nature reserves or at certain piers such as Brighton Pier, just an hour's train journey from London.
The murmurations are most common in winter, November being the best month.
See the RSPB website for details on where and when to see them.
16. Santa Maria della Salute, Venice, Italy
Because they've been the subject of so many Renaissance paintings, the iconic landmarks of Venice stop the heart when you see them for the first time.
The Rialto, the Bridge of Sighs, the vast expanse of San Marco look much as they did 400 years ago, but nothing evokes the mystery of La Serenissima quite like the Basilica di Santa Maria della Salute looming out of the mist at the entrance to the Grand Canal.