Paricutín is one of the youngest volcanoes on Earth and one of the rare geological events witnessed from birth by living people. It emerged from a corn farmer's field on 20 February 1943 and erupted continuously until 1952, burying two villages in lava and ash. What remains is a stark 424-metre cinder cone rising from a hardened lava field, with the tower and roof of the San Juan Parangaricutiro church still visible above the lava flow — a famously surreal image.
The standard approach is from the indigenous Purépecha town of Angahuan, about 25 km north of Uruapan. From there, local guides on horseback lead visitors across the lava field to the buried church ruins and up to the base of the cone itself. The full day excursion — out to the church, up to the crater rim, and back — takes about 8 hours on horseback and is genuinely strenuous. You can also hire a horse just to the church ruins and walk back, a shorter option that still captures the essential strangeness of the site.
The lava field is rough and disorienting; do not attempt it without a guide.