Calamba City Day, observed in Calamba, Philippines, is celebrated every April 21 to commemorate the signing of the Calamba Charter in 2001. This special non-working holiday marks the anniversary of the plebiscite that granted Calamba cityhood. Calamba, known as the "Spring Resort Capital of the Philippines," is famous for its hot spring resorts and as the hometown of national hero José Rizal. The city's name, derived from the Tagalog word "kalamba," refers to a wide-mouthed earthenware water jar, symbolized by the Calamba Jar, the largest clay pot in the world located at the City Plaza. The city has a rich history, with pre-Hispanic settlements and significant events during the Spanish colonization and World War II. Today, Calamba is recognized as the richest city in the Calabarzon region, with its economy driven by manufacturing, IT, banking, tourism, agriculture, and services.