National Monument, Gambir

After arriving the big parking lot, you can take one of the horse-cabs that will give you a ride to the foot of the statue. This is recommended, because it is a long way to walk in the heat. I think I paid 20.000 RP. You can walk the underground leading from one side of the open space, to the entrance of the Monument. The underground is a pure tunnel, nothing extra to it.
The elevator leads to the top, giving a great view over the city. You should finish the tour by visiting the basement, which is the the best part.
The indonesian story is illustrated by a small sceneries, and you walk from window to window reading about the different periods and conflict that this region has suffered under. It gives a great perspective of the imperialism during the dutch period as well.
Finally, you can see (interactive) the development of the Jakarta city, shown in a modern stage in the same basement. Conclusion: The basement is best, I didn't find the monument in itself so interesting.