The biggest blue fire area in the world & Sukamade turtle beach in Meru Betiri National Park 
The biggest blue fire area in the world - Meru Betiri NP
The blue fire can only be seen when it is dark, which doesn't mean that 'it' isn't there during the day. If you wish to see this spectacular event, you will have to depart at midnight. It is a two hours drive from Bondowoso to Paltuding, from where your hike to the Ijen crater lake - also called kawah Ijen - starts. A local guide, obligatory, will lead you in the dark up the mountain and into Ijen's crater. In the crater, you can see the blue fire from nearby.
When the sun is about to rise, you can make your way up to the crater rim to see the landscape changing faces in the early morning light.
If you wish to skip the trip to see the blue fire, 05.00 is a good time to depart to Paltuding. You will arrive around 07.30 at the top of Mt. Ijen from where you will have colorful views over the most acidic lake in the world, while sulphur miners are at work, carrying baskets of about 80 to 100 kg out of the crater. Once at the crater rim, the sulphur is reloaded on trolleys that are wheeled down Ijen's slopes to the sulphur weighing area just behind the parking lot.
When ready, meet your driver to continue to the Meru Betiri National Park.
You will change cars in Jajag, as once again you will need a 4wd. The route to the park is scenic. You will see some beaches and plantations and some rivers will have to be crossed as well. You will arrive late afternoon. Heading to Sukamade turtle beach is certainly off the beaten track and it requires some effort to reach the National Park and the beach, but it is very worthwhile indeed!
The turtles come ashore during the evening starting from 19:00 and depart again around midnight. A ranger will guide you to the beach and together you will wait for the turtles. Seeing a turtle coming ashore is a special moment. Watching these impressive creatures emerge from the surf and struggle-up the beach to lay their eggs on a moonlit night is an unforgettable experience. After the turtle found its spot on the beach, the turtle will dig a hole for her eggs. Some rangers will take the eggs and bring it to the hatchery as part of the conservation program, carried out since 1972.
Although the turtles come ashore almost every night, it isn't a guarantee that you will meet the turtles.
Accommodation: Ranger's Lodge - basic homestay and electricity till 21:00
Note: please understand that hiking down into Ijen's crater is officially forbidden at any time. Therefore hiking down into the crater will be at your own risk.