Bhubaneswar makes an excellent base for day trips. Nandankanan Zoological Park, 20 km from the city, combines a botanical garden, zoo, and wildlife sanctuary in lush surroundings. The twin hills of Udayagiri and Khandagiri, just 7 km away, hold rock-cut caves dating to the 1st-2nd century BC, carved for Jain monks by King Kharavela. The Hathigumpha (Elephant Cave) and Rani Gumpha (Queen's Cave) are the most impressive.