Casa de las Sierpes, Colonial building in Cusco, Peru.

Casa de las Sierpes is a colonial mansion on the Plazoleta de las Nazarenas, 300 metres from the Plaza de Armas. Its Inca walls carry snakes carved in high relief, and the doorway lintel holds two sea-lion-headed sirens flanking a shield with the initials PQB, a royal crown above and a skull below. A bell tower that crowned the portal collapsed in the 1950 earthquake.

The house stands on the site of the Inca Yachaywasi, a school. After the Spanish conquest, the lot was granted to soldier Mansio Sierra de Leguízamo, giving the house its first name, Casa Leguizamón. From 1644 to 1673 it housed the Colegio San Francisco de Borja, and in 1715 the Beaterio de las Nazarenas was founded here, becoming a monastery in 1760.

The house takes its name from the snakes carved in high relief on its Inca walls, which belonged to the Yachaywasi, the Inca school that stood on this plot. The small square outside was called Santa Clara la vieja until the Nazarene beaterio moved in, after which it became the Plazoleta de las Nazarenas.

The building is now the Belmond Hotel Palacio Nazarenas, opened in 2011, so the interior is not open to casual visitors; only hotel guests and patrons of its restaurant or bar enter. From outside, the Plazoleta de las Nazarenas, about 300 m from the Plaza de Armas, allows a close look at the doorway with its two carved sirens and the initials PQB.

The building's foundation features original Inca stone blocks fitted without mortar, supporting colonial-era upper sections and balconies above. This layering directly shows how Spanish conquistadors integrated existing structures into their own designs.