This is Eulychnia Acida, also known as Copao. This protected plant produces a fruit about the size of a grapefruit. This cactus can live up to 100 years old, and is endemic to Chile. The blossoms are mostly white with some pink petals. This plant prefers full sun and can withstand being planted in dry soil. The plant is known to attract several different butterflies, and is commonly used as a larval host plant. USDA Hardiness Zones 10 to 11