Tijuana
In short
Tijuana is the largest city in the Mexican state of Baja California and serves as a major hub for the San Diego–Tijuana metropolitan area. It sits directly on the border with the United States.
In plain words
It is a massive, busy city located right next to California. Because it is on the border, many people cross between the city and San Diego every day for work or shopping.
A simple example
A person might live in Tijuana to save on housing costs but drive across the border into San Diego to work in a tech office.
Why it matters
It is a vital centre for trade, tourism, and transport between Mexico and the USA. Its location makes it one of the most important economic zones in northern Mexico.
Easy to mix up
Do not confuse the city of Tijuana with the entire state of Baja California.