Nowadays, Celaket 21 is a name used to call a school located on Jl. Jaksa Agung Suprapto. The number 21 is of course its street number. I don’t really know what the building was used in the past. According to its similarities to the Ursulines Monastery building that is only 300 meters to the north from Celaket 21, I guess they were built at the same period of time. Ursulines Monastery building was built in the early of 1900’s. Some say that there is a tunnel connecting these two buildings.
The Brothers of BHK began to use the building from 1928. Now, the Celaket 21 is used by the Brothers of BHK. The building is also used as a Mardi Wiyata Junior High and Elementary School.