Baguio has a rich and interesting history, both culturally and, more significantly, geologically. As early as 1572, Spanish colonizers attempted to conquer the indigenous people in the cool mountains of Benguet. But it was not until 1846 that they were able to gain a foothold in the area when Commandante Guillermo Galvey established a military garrison in the verdant La Trinidad Valley, named after his wife.

The Americans found particular delight in the pleasant weather of Baguio City. In 1904, U.S. Secretary of War and former Governor­-General of the Philippines William Howard Taft commissioned the preparation of plans for the development of Baguio as the summer capital of the Philippines.

Baguio City, which now lies approximately 1,540 meters above sea level, began as a succession of rocks that piled up over millions of years. The oldest rock formation – “Pugo Formation” composed of basalt, lava flows and siltstones – was produced from volcanism and sedimentation thousands of meters underwater over 35 million years ago. The youngest rocks belong to the Baguio Formation, comprised of lava flows and tuffs, conglomerates, and sandstones. The deposition of the Baguio Formation is believed to be synchronous with the phase of magmatism associated with the copper and gold mineralization in the Baguio mineral district.

Mirador Hill, where the Grotto of Our Lady of Lourdes was installed by the Jesuits in 1913, is the type locality for the Mirador Limestone. The limestone was deposited between five and 23 million years ago in shallow and calm, warm marine waters. That type of environment is where organisms capable of forming calcium carbonate shells and skeletons can easily extract the needed ingredients from ocean water. When these animals die, their shell and skeletal debris accumulate as sediment that might be lithified into limestone. Their biological origin is often revealed in the rock by the presence of fossils.

Fascinating information about the rocks of Baguio, intertwined with facts about various landmarks around the City of Pines, form the basis of the Baguio GeoTour.

As part of GeoTours Philippines, one of the flagship projects of the University of the Philippines Geology Alumni Association (UPGAA), the experiences offered consist of guided geological, educational and cultural tours to interesting sites and monuments. Leading the way are geologists, mining engineers and geoscientists. The UPGAA, in cooperation with the Philippine Mine Safety and Environment Association, Inc. (PMSEA), launched the Baguio GeoTour in 2013 during the 60th Annual National Mine Safety and Environment Conference. Participants included mining engineers, geologists, lawyers and various staff of the mining companies and government agencies and their families who gathered in Baguio for the conference.

The tour brought participants from Camp John Hay to the Asin Hot Springs to enjoy panoramic views of Baguio City and discover the lithostratigraphic relationships of the rocks along the way. Other stops included the Asin Tunnels, constructed by prisoners of war during the mid­19th century; the Shrine of the Brown Madonna, a Catholic chapel built in 1988 within a supposed continuation of a tunnel for a railroad line from Aringay, La Union to Baguio City during the American period; and the BenCab Museum, a collection of galleries showcasing the genius of 2006 National Artist for Visual Arts, Benedicto Cabrera.

In 2014, the geotour featured the Balatoc Mines, Mines View Park and Tam-Awan Village. Visitors to the Balatoc Mines got to ride the underground locomotive train to the famous Vegas Tunnel and learned about the different stages of the process of gold mining, while wearing complete outfits with the proper safety gear.

For lunch, they motored to Crosby Park in Itogon, Benguet. The park, located in a six­-hectare pine forest, sits 1,150 meters above sea level and offers a spectacularly scenic view of mountains, deep valleys, gorges and rolling slopes. At Tam­-Awan Village on the outskirts of Baguio City, they explored this artists’ colony set amid a charming collection of Ifugao and Kalinga huts. In the local idiom, tam­-awan means “vantage point”, an apt name for the colony that sits on a hillside and affords a magnificent view of the South China Sea on a clear day.

On the way back, participants got goose bumps as they explored the Dominican Hill and Retreat House, which always figures in the list of most haunted places in the Philippines. Some years ago, the now-abandoned building, erected by the Dominican friars in 1911, gained notoriety after the release of a horror film starring Gretchen Barreto. For this eclectic mix of science and culture, the Baguio GeoTour was nominated for the Baguio Midland Courier’s 2014 Tour of the Year.

Delegates to the 62nd Annual National Mine Safety and Environment Conference from November 17 to 20, 2015 will be treated to the latest edition of the Baguio GeoTour. This year’s itinerary will take them from Camp John Hay to Sitio Pungayan, Tuba, Benguet, better known for its fictional name of “Sitio La Presa” in a popular television series, as well as other geological and cultural