233503
the 18-metre high , 220-ton stone structure is situated on a huge roundabout called Plaza del Obelisco , where the Avenida Reforma , Boulevard Los Próceres , Avenida Las Americas and Boulevard Liberacion meet .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None