Back ground on my Historic Center of Mexico City posting: after our first day of meetings in Mexico City, I got a ride over to the Historic Center and went for a walk. I started at the Palacio de Bellas Artes, the beautiful Art Nouveau opera house, walk east on Calle de Tacuba to the Zócalo / Plaza de la Constitución.
I briefly saw the historic plaza. I then walked back to the opera house via the famous Calle Madero pedestrian shopping street.
Along the way, I saw Torre Latinoamericana skyscraper, Banco de México, Edificio de Correos / Palacio Postal, MUNAL / Museo Nacional de Arte, El Caballito equestrian statue, Palacio de Minería, Museo del Ejército y Fuerza Aérea, Biblioteca del Congreso de la Unión, Zapaterias leon shoe store, Metropolitan Cathedral, Hotel Majestic and Gran Hotel, Palacio del Ayuntamiento, Edificio La Mexicana, Templo de San Felipe Neri, Palacio de Cultural Banamex, Edificio High Life, Templo de San Francisco, Casa de los Azulejos, and finally the Benito Juárez Memorial.
Later that evening my hotel told me that it was a protest. I never sensed any hostility, but overall I think it was good that I only stayed briefly.
As a general practice, the security organization at my work asks all travelers to Mexico City to only use pre-arranged cars. My hotel was happy to help. To get to the Centro Histórico my hotel gave me a ride; to return, they arranged for me to get a ride from the Hilton right next to the Bellas Artes.