Cultural heritage sites face increasing threats from climate change, urbanization, and tourism impacts, while traditional preservation methods struggle with accessibility and engagement challenges. This interdisciplinary study develops augmented reality (AR) applications for cultural heritage preservation and education, focusing on ancient sites in Greece, Jordan, and Colombia. We created photorealistic 3D reconstructions using photogrammetry and LiDAR scanning, integrating historical data and archaeological findings into immersive AR experiences. User testing with 892 participants across different age groups revealed 89% improvement in historical knowledge retention and 94% increase in cultural engagement. The research provides open-source frameworks for democratizing cultural heritage preservation and education globally.