Poás is another of Costa Rica's most active volcanoes. The colorful summit craters comprise a popular attraction, and are accessible by vehicle. The 2,708 meter stratovolcano lies within two vast calderas*. The southernmost of two summit crater lakes, Botos, is cold and clear, and last erupted about 7,500 years ago. The other is warm and acidic and has been the site of frequent eruptions since the first was reported in 1828. Eruptions often feature geyserlike ejections of lake water.