La Union Watchtowers

The province of La Union in the Philippines has various Spanish colonial watchtowers (bantayan) which are recognized as National Cultural Treasures since 2014.

Background
The Spanish first colonized the Ilocos Region in 1572. They would build large stone structures such as churches and forts in the following years. Watchtowers were built for sentry purposes against Moro and Chinese pirates as well as other European colonial powers.

The fortifications are mostly built using coral blocks held together by lime and egg whites. In the contemporary period, the fortifications fell into disuse and many are in a neglected and damaged state.

At least the Luna Watchtower was however used by the Americans during the Japanese occupation era of World War II.