I visited Masjid Jami Al-Anshor, the oldest mosque in Jakarta, during ramadan. It is a bit hard to find as it is located inside tiny streets of the Tambora district in North Jakarta. You will probably need to ask your way several times to local residents. I was just going around saying "Saya cari masjidnya yang paling tua di Jakarta" and amused kids led me to it.
One of the small gangs leading to the Mosque
Al-Anshor was built in 1648 and unfortunately, there are not many parts of the original structure that remain visible today. The old wooden floor was removed a few years back when the structure was elevated to avoid floods. Apparently, the only original parts left are the small graveyard, the wood in the tower and the water room. Renovation works are going on, apparently paid by the residents themselves. I was surprised that the city of Jakarta is not trying to protect this historical sight better.
Still, I recommend you a visit if you want to experience the "real" Jakarta. First by walking and losing yourself in the "gangs" and second by meeting worshippers. Though I'm not muslim and not exactly a religious guy, I was invited to break the fast with the residents who were very welcoming and proud of their mosque. They later took me to the Annawier Mosque and the Langgar Tinggi Musholla that I will review separately later.
For those wondering why I'm reviewing a Mosque: I will write more about all attractions and things to do in Jakarta in the coming months, including all Jakarta museums, shopping malls, religious sights, colonial buildings, parks, etc. 

Masjid Jami Al-Anshor 
Oldest Mosque in Jakarta
Jalan Pengukiran II, No 6, Rt 006 RW 04
Kel Pekojan, Kecamatan Tambora, Kodya, West Jakarta
Phone number: +62 (0) 6914 356 or +62 (0) 6930080

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