Tangkuban Perahu last erupted in 2019, releasing ash plumes that closed the crater rim for eight months. The 2,084-metre stratovolcano sits 30 kilometres north of Bandung, reachable from Jakarta in under four hours via the Purbaleunyi toll road. Its name translates to "upturned boat," a reference to the ridgeline's silhouette when viewed from the southern plain. Dutch colonial surveyors mapped the caldera system in 1829, identifying three distinct craters: Kawah Ratu, the largest and most accessible; Kawah Domas, a shallow sulphur pool where visitors once boiled eggs in fumarole vents; and Kawah Upas, the smallest and least visited. The conservation area surrounding the volcano spans 1,200 hectares of montane forest, administered by Perum Perhutani and open daily from 07:00 to 17:00. A paved access road climbs to within 200 metres of Kawah Ratu's southern rim, allowing visitors to walk directly to the observation deck without descending into the caldera. The crater floor emits continuous sulphur vapour, and seismic monitoring stations ring the summit to track magma movement beneath the cone. Foreign visitors pay a 200,000 IDR conservation fee on weekdays, reduced from the 2018 rate of 300,000 IDR following a decline in international arrivals during the pandemic years. Jakarta volcano day trip itineraries typically pair Tangkuban Perahu with secondary stops in Lembang, a highland town known for tea plantations and geothermal springs. The route north from Bandung ascends through pine forests and smallholder vegetable farms that supply the city's wholesale markets. Most guided excursions depart Jakarta before dawn to reach the crater rim by 09:00, when cloud cover is lightest and visibility extends across the caldera to the northern ridge. The return journey often includes a detour to Ciater hot springs, a developed resort area 15 kilometres east of the volcano, where sulphuric water is channelled into tiled pools. The volcanic arc that includes Tangkuban Perahu stretches from Krakatoa in the west to Mount Merapi near Yogyakarta, part of the Sunda subduction zone where the Indo-Australian Plate dives beneath Sundaland. Geologists classify Tangkuban Perahu as a polygenetic volcano, built from multiple eruptive cycles over the past 40,000 years. The current cone replaced an older structure that collapsed during a Plinian eruption, leaving the horseshoe-shaped caldera visible today. Fumarole temperatures at Kawah Ratu average 80 degrees Celsius, and the crater lake's pH hovers near 1.5, acidic enough to corrode metal observation railings within a season.