Saphan Pi Kun is a pedestrian bridge across Khlong Lord in Rattanakosin. It was built by Queen Somdet Phrasri Phatcharinthra Phraborommarachininat, the consort of King Rama V in 1911. It was to commemorate her 48th birthday, which is an auspicious completion of the 4th cycle of the Buddhist zodiac, on the Year of the Pig. For that reason, it got the name Saphan Pi Kun, which means Pig Year Bridge.
Saphan Pi Kun has four pillars, two on each end, decorated birthday candles, to commemorate the fourth cycle. The oval plates on each post also means the "cycle" of the birthday.