Best time to go to Ijen Crater is in the early morning, it's about 4 a.m., after a few hours of half sleep. In the morning we  can find sulphur collector begin their job. The silence was magnificent. The only sound heard at these heights was the  soughing of the wind in the cemara trees. Audible for several kilometres, the wind could be heard whistling around the rim of  the caldera, sometimes taking a full minute to reach us.

As dawn approached we set up cameras overlooking the plateau to the west. Immediately in front of us stood the monstrous  crater of Mt Raung, which at 3,332m is the highest peak in the vicinity and among the tallest in Java. Raung is an active and  dangerous volcano, which is known to erupt regularly.Prior to 1838 the crater probably contained a lake, which would have  caused extensive flood damage during eruptions. Nowadays, however, the crater floor is dry. From the air, the gaping summit  of Raung presents an awesome spectacle, the sheer crater walls plunging half a kilometre into the heart of the mountain.

In the central Javanese city of Solo, a statue of Gesang Martohartono looks over the gently flowing Bengawan Solo, or Solo  River.

It was the famous Indonesian singer-songwriter Gesang, who composed the celebrated Indonesian melody "Bengawan Solo" during  World War II -- when the country was under Japanese occupation.

"Bengawan Solo, this is a song of your history. People have been fascinated with this great river since ancient times, Around  the source of the Solo River, there are a thousand mountains, and the river flows all the way to the sea.