Wat Yannawa means the Temple of Junk: specifically, the temple of the concrete Chinese junk put in place by King Rama III. This monument is named Samphao Chedi (Junk and Chedi). The interpretation board in the Wat has this to say:

• This Temple is an old one dating back to the Ayutthaya period, the founder is unknown, commonly called Wat Khok Khwai (Stable for Buffaoles). King Rama I ... made it a Royal Temple. In the reign of King Rama III, trade connection with China was bloomed and the Chinese Junks were used to carry all kinds of cargo, with concern to the vanishing of this junk, King Rma III ordered to build a monumentally imitating Chinese junk.

Two Chedis take the place of poles in the architecture of the junk. The monument is 43 metres in length and is said to be the only one of its kind in existence.