I heard about ijen via a Tripadvisor forum and I am so thankful for every review that encouraged me to make the tough trip to get there- it's worth it. We flew into Bali, took an excruciatingly long drive to Gilimanuk Ferry from Denpasar. took the ferry to Banyuwangi, stayed overnight and started climbing at 2am. The climb is STEEP. And the road is slippery. We got by wearing sneakers, but if you have hiking boots, this is the place to put them to use. The night sky is stunning while you climb and the sunrise is worth the tough climb. Its a 3km walk till the crater rim, and another 1km if you want to get to the sunrise point. The terrain is magnificent. Unfortunately we got there on a cloudy day, and we couldnt get a clear view of the lake, but even so- it was stunning. Carry gas masks- the regular N95's from a pharmacy will do. The last 1 km walk the fumes are very strong. Beyonfd the rim of the crater if you want to go down they will provide you the gas masks (professional grade)- we didnt make go down as the climb was very steep and the fumes extremely strong. There are mining workers doing their daily job there. As a fellow traveller I urge you not to stop them to click pictures- we are there for recreation, they are not. And its a tough, inhumane job they do. It was sad to see other tourists clicking pictures and posing with them interrupting their walk up from the mines. The climb down from Ijen is tough too- your knees will take a beating! If you have trekking poles, they are very handy here. Overall, ijen is one of those fabled places you see in Star Trek or in a Nat Geo documentary. If you have the opportunity to visit, dont miss it.