Yogyakarta is the cultural heart of Indonesia. The city is located on Java Island. It is a 7-hour train journey from Jakarta. There is a lot to do in Yogyakarta and its surroundings.
The city has a busy and enjoyable street life with several points of interest such as the Water Palace and the Kraton Palace. Everything is within walking distance. You can also learn about Batik. It is an Indonesian painting process using boiled wax on cotton. If you are lucky enough and able to easily engage a discussion with locals, some might even drive you around for free as I experienced. I find Indonesian people to be curious and always happy to discuss with foreigners.
Yogyakarta’s surroundings feature two of the most emblematic places of worship in Indonesia. Both are noted as UNESCO Heritage Sites. Borobudur is a 9th-century Mahayana Buddhist temple and Prambanan is the biggest Hindu temple in the world featuring 240 pieces of temples (which was created in 856). The sunrise viewpoint next to the Borobudur temple is literally one of the most beautiful sunrise scenery I have ever seen in my life! It is definitely worth waking up at 3 am.