Final answer:
A bulbous stone finial of a sikhara is called a Kalasha. It is typically found on Hindu temples and represents prosperity. The Khalsa Heritage Memorial Complex incorporates such traditional design elements in its architecture.
Step-by-step explanation:
The bulbous stone finial of a sikhara is known as a Kalasha. This architectural feature is characteristic of the North Indian temple architecture, specifically in Hindu temples. It is a dome-shaped cupola and symbolizes a coconut, signifying prosperity and good fortune, and is often placed atop the temple's sikhara or tower.
Regarding the reference information provided, the monumental ceremonial center in Indus Valley cities may have been a citadel, as this is where evidence suggests religious activities may have been centered. The Mahabodhi Temple is an example of classical Indian temples, featuring a traditional structure with an amalaka and a kalasha. The Indus Valley civilization was known to the Mesopotamians as Meluhha.
The Khalsa Heritage Memorial Complex is a contemporary example related to Sikh history, which integrates traditional elements like domes associated with Sikh architecture, similar to the finials or kalashas on ancient temples.