Thailand's first capital has the most interesting and varied ruins in the country. The centerpiece of the town itself is a large monastery. Nearby is a colorful and fascinating market. Wat Mahathat has an abundance of Buddha images. If you're not joining an organized tour, catch a songthaew (a truck that serves as a bus) or hire a cab (be sure to negotiate the fare before getting in) to take you to the ruins. They're fairly spread out (many are hard to find), so a taxi driver or other guide is essential. It takes a full day to see all of the ruins. Bicycle rentals are also available. There are more ruins nearby at Si Satchanalai, known for its many stupas and temples. 280 mi/450 km north of Bangkok.