Today the 1,077-plus acre Longwood Gardens consists of 20 outdoor gardens and 20 indoor gardens within 4.5 acres (18,200 m²) of heated greenhouses, known as conservatories. It contains 11,000 different types of plants and trees, as well as fountains. The Gardens also has extensive educational programs including a tuition-free two-year school of professional horticulture, a graduate program, and extensive internships. It hosts 800 horticultural and performing arts events each year, from flower shows, gardening demonstrations, courses, and children’s programs to concerts, organ and carillon recitals, musical theater, fountain shows, and fireworks displays. It also hosts an extensive Christmas light display during the holiday season.