Sorrel not only clicks up the kilometres in amazing Mexico City but she is about to discover the myths of the Aztecs.
The population of Mexico is thought to be around 105 million and Mexico City's population estimated at somewhere between 18 and 20 million.
Mexico City is 1.5 km above sea level and built on the ruins of Tenochtitlan, the ancient Aztec capital. Reminders of past civilization are everywhere the Templo Mayor excavation and the superb Anthropological Museum at Chapultepec Park.
Before Christopher Columbus headed to the New World, the Valley of Mexico was a centre of commerce. Founded in 1325, it is the longest continuously-inhabited city in the western hemisphere.
The Zócalo, built in 1520 as the heart of the Aztec empire, is the hub of modern-day Mexico. Its full name is the Plaza de la Constitución, but it's called Zócalo, the Spanish word for stone base, a name adopted in 1843 when a monument to independence was constructed only as far as the base. Many Mexican cities and towns have adopted the name for their main plazas.
Each day conchero dancers remind everyone of the heritage of the area, dressed in feathered headdresses, shell anklets and bracelets and accompanied by booming drums.
Cortés had the plaza paved with stones from the ruins of the Teocalli and nearby Aztec buildings. With each side measuring over 200 metres, it is one of the world's largest city plazas. On its eastern side is the National Palace, on the northern side the Metropolitan Cathedral and on the southern side, the Government of the Federal District is housed in two 1532 buildings which were rebuilt in the 17th century. This makes it a popular place for political protesters. The huge flag flying in the centre of the Zócalo is lowered at 6pm each day by soldiers of the Mexican army.
Mexico's National Museum of Anthropology in Chapultepec Park is one of the world's finest. For a deeper understanding of Aztec history and culture, it is not to be missed.
In the early 1960s, the enormous showcase evolved as the result of close co-operation between architects, museologists, anthropological researchers, artists, designers and engineers. Its 26 halls hold one-of-a-kind exhibits; each hall is independent. It is the mecca of Meso-American history, with halls dedicated to Olmec, Aztec, Toltec and Mayan cultures, their predecessors and lesser cultures.
There are dioramas and models depicting the appearance of Meso-American cities at their height, including Tenochtitlan, a city of bridges and canals which stunned the Spanish when they first saw it.
There are thousands of objects on display, including ceramics, sculptures, architectural decorations, toys, tapestries and frescoes in excellent condition. Labelling is in Spanish, but most objects simply speak for themselves and need no written explanation.
Just one kilometre south-east of the Zócalo is La Merced market. Occupying four blocks of large, modern buildings, it is dedicated to Mexicans' daily needs food, clothing, crockery, cutlery and is a good place to try local cuisine. These markets give a good feel for local life and are terrific for a browse.
A couple of blocks south is the exotic Sonora Market, with four diverse specialities toys, caged birds, herbs and folk medicine. There are 10 market witches on hand who say they can cure a sore throat, broken heart, cleanse your soul or bless your fate, all for around $5!
Best Western Hotel Majestic is perfectly positioned for tourists, right on the Zócalo. The seven-storey hotel's Terraza Restaurant on the rooftop has wonderful food and views. Sunday brunch is taken to the accompaniment of mariachi music.