I recently read about Elephant Cave near Phong Nha-has anyone been there? What’s unique about it compared to Paradise or Dark Cave? Is the cave entrance well-marked, and how long is the trek to reach it? Are there any fees or local guides required? I’m intrigued by stories of ancient carvings or unusual rock formations inside. Did you find the hike strenuous, and is it suitable for families with kids? Any recommendations on the best time of day to visit and what to pack would be really helpful.