Ancient Indian temple architecture is a rich and diverse tradition that has evolved over thousands of years, with influences from various regions, cultures, and religious beliefs. The architectural styles of Indian temples can be broadly classified into three main categories: Nagara, Dravida, and Vesara. Each of these styles has distinct characteristics and features.

1. Nagara Style:
   • Geographical Influence: Primarily found in northern India.
   • Characteristics:
     • Tower or shikhara is a prominent feature, usually with a curvilinear shape and a beehive-like appearance.
     • Multiple stacked horizontal sections (storeys) with gradually decreasing size.
     • Amalaka (a stone disk) and kalasha (a pot-like structure) on top of the shikhara.
     • Mandapa (hall) in front of the sanctum.
     • Ornate entrance with intricate carvings and sculptures.
2. Dravida Style:
   • Geographical Influence: Predominantly found in southern India.
   • Characteristics:
     • Vimana or shikhara is pyramidal in shape and is composed of several horizontal tiers.
     • Square or rectangular base with a smaller, domical structure on top.
     • Typically lacks a mandapa or has a simpler one.
     • Enclosed prakara (compound wall) around the main shrine.
     • Large and elaborate gopurams (entrance towers) with intricate sculptures.
3. Vesara Style:
   • Geographical Influence: Found in central India and other transitional regions.
   • Characteristics:
     • Combination of features from both Nagara and Dravida styles.
     • Shikhara with a pyramidal shape but not as elaborate as in the Dravida style.
     • Sometimes includes a domed structure.
     • May or may not have a mandapa.
     • Varied ornamentation, reflecting a fusion of northern and southern elements.
4. Other Architectural Elements:
   • Mandapa: A pillared hall used for religious and cultural activities.
   • Garbhagriha: The sanctum sanctorum where the main deity’s idol is enshrined.
   • Shikhara/Vimana: The towering structure over the sanctum, representing the cosmic mountain or the abode of the gods.
   • Gopuram: An ornate and often monumental entrance tower, especially in Dravida style temples.
   • Amalaka and Kalasha: Decorative elements placed on top of the shikhara, symbolizing cosmic and ritual significance.
5. Inscriptions and Sculptures:
   • Temples often feature intricate carvings depicting mythological stories, deities, celestial beings, and scenes from daily life.
   • Inscriptions provide valuable historical and cultural information.

Prominent examples of ancient Indian temples include the Khajuraho temples, Konark Sun Temple, Brihadeshwara Temple, and the temples of Varanasi, among many others. The diversity in architectural styles reflects the cultural, regional, and religious variations that have enriched India’s heritage.