TEMPO.CO, Jakarta - The warning sign forbidding travelers not to venture within 1.5 kilometers of the summit of the Ijen volcano did not deter Hendri Irawan, 22, from Banyuwangi, East Java. The temptation to behold the caldera's wonder was too great.

Last year, Banyuwangi's Disaster Mitigation Board placed the crater under high alert. Warning signs have been put up along the road that leads to Paltuding Post, the starting point for the trek to Ijen.

To Hendri and other climbers, the crater lake's unusual beauty outweighs the risk of an eruption. During the day, the water takes on a tosca-green hue, while the the lake's bottom appears yellow. In the bright sunlight coupled with the blow of a mountain breeze, the tosca hue mingles with white smoke billowing from the layer of yellow sulphur on the caldera walls.

At twilight, the lake gives off a bright blue haze mixed with white plumes. A whitish blue incandescence resembling that from a giant fluorescent bulb is visible from the peak at night.

Hundreds of domestic tourists, as well as people from other countries in Europe and Asia, are enchanted enough by the possibility of seeing this spectacle to make the climb. The soccer-field-sized parking lot at Paltuding Post is almost always crammed with motorbikes and cars.

Sulphur-mining can also be watched. At any given time, hundreds of miners using traditional techniques can be seen in action. They descend into the caldera, then climb back up the walls, carrying the substance.

Mount Ijen's tourist area is managed by East Java's Natural Resources Conservation Center III. Sunandar Trigunajasa, the head of the center, said tourists were allowed only as far as Paltuding Post while the volcano is on alert. "Tourists can still enjoy agro-tourism looking at coffee plantations or the Belawan waterfall, which are no less wonderful," he said.

Head of neighboring Bondowoso district's Tourism, Sports and Communication Service, Bambang Soekwanto, said Ijen's peak has been a popular destination for several decades. The Bondowowo government needs to improve roads and infrastructure, he added. "We have plans to develop the villages around Ijen into tourist villages," he said.

Those who seek to reach the summit must travel 60 kilometers from Bondowoso to Sempol. At the last village, tourists can take an ojek (motorcycle taxi), which should cost around Rp75,000, to the Ijen area. During the trip, visitors can see where local people live and grow coffee and cocoa.

Visitors can stay in villas operated by the Forestry Ministry for Rp100,000 a night. The lodgings lie only about 500 meters from the starting point of the Ijen trek. Those who prefer more comfortable accommodations can stay at a guest house belonging to Perkebunan Nusantara XII at the Belawan Coffee and Jampit plantations.

EKO ARI WIBOWO | MAHBUB JUNAIDY | IKA NINGTYAS