First of the misions: Mision Loreto, BCS.
The Jesuits started at Loreto and founded a total of 17 other missions in Baja California, including nearby San Javier, which is about 20 miles from Loreto in the height of the Gigantas. After the Jesuits, the Dominicans and then the Franciscans under Junipero Serra and others went on northward building more missions in the northern Baja, and beginning in 1769 to build the famed chain of missions in what is today the US state of California. But Nuestra Senora de Loreto was the first of all these missions, and remains the spiritual root from which the rest flowered.
The Loreto mision was founded in 1697; construction of the mission church began soon thereafter, and it remains in use today.
Almost immediately after the establishment of Loreto, in 1699, a small group under Padre Piccolo hacked out a foot route, over 20 miles long, up the sheer face of the Gigantas and into an upland valley known as Vigge Biaundo (the name is one of the few things left from the original Indian inhabitants), to the site of San Javier. Construction of the mission church began there in 1744 and took about 15 years. It was built from stone quarried nearby. In its interior, the main altar and two side chapels are stunning examples of the religious art of the era, brought laboriously to the site by the misionaries and the faithful.