Tijuana (Aug. 29, 2019):
Baker
Los Angeles
Monterey
San Diego
San Francisco
Saint Joseph
Saint Louis the Bishop
Santa Barbara
Solvang
They're not from California, but I'm adding them because we also did them on this trip:
Grand Canyon (Arizona)
Las Vegas (Nevada)
Tijuana (Baja California, Mexico)
A brief history of Tijuana:
Origins:
The area where Tijuana is located today was originally inhabited by the Kumiai, an indigenous people who occupied the region between northern Baja California and southern California. In the late 18th century, Spanish expeditions began exploring the area, although no significant settlements were established until the Mexican period.
Middle Ages:
There is no equivalent Middle Ages in this territory; during that European period, the region continued to be occupied by indigenous communities with their own social and cultural systems, without influence from Western medieval development.
19th Century:
Tijuana began to take shape in the 19th century after Mexico's independence. The establishment of cattle ranches, such as Rancho Tía Juana, marked the origin of the settlement. With the signing of the Treaty of Guadalupe Hidalgo in 1848 and the definition of the border with the United States, the area gained greater commercial and strategic importance.
Present:
Today, Tijuana is one of Mexico's largest and most dynamic cities, renowned for its bustling border activity, manufacturing industry, cultural and culinary growth, and its pivotal role within the binational Tijuana–San Diego region. It is a key economic hub in northwestern Mexico.
It's not worth it at all, it's a dangerous city and it really has nothing, except a street of prostitutes and little else.
We went down to Tijuana because it was close to San Diego and so we could say we crossed into Mexico 😅.
We pulled into a guarded outdoor parking lot to leave the car "safely" until the owner saw us get out. She looked us up and down and practically said, "Where are you going, white boys?" She told us to get the hell out of Tijuana, but not before driving down the street of "friendly women" with the windows rolled up and the car locked, to see what she considered the only attraction the city had. We took her advice. She recommended we go a little further down to Pueblo Nuevo, where we went to try the lobster at a very low price.
On the way back we also stopped at the beaches of Rosarito to confirm their fame, and where we can confirm that in Spain we have immensely better beaches.
It was very windy, they were very dirty, and the water was freezing.
As expected, we went into a murky/dangerous area where we were escorted out by a military car.
Recommendation: avoid sunset to enter the US, queues of more than 2 hours form, and the customs office is a Mexican street market.
Tijuana goes very well with San Diego because of their proximity and because they allow you to connect two countries in the same trip between city, urban culture and Pacific coast.
Information obtained from the web https://www.exteriores.gob.es
Passport: It is suggested that the passport be valid for at least 180 days, since that period coincides with the maximum stay in Mexico as a tourist.
Round-trip plane ticket.
Visa: It is not necessary for tourism.
Vaccines: There are no mandatory vaccinations for entry.
International driving permit: It's not mandatory, but it is recommended. You can request it through the website. DGT.
It costs €10.51. The good thing is you can order it online and pick it up without an appointment. It took a couple of days for ours, then you go to pick it up and it's a cardboard card like the ones they had 20 years ago.
Travel insurance: It is recommended to have road insuranceHeh. The best known and most complete ones are Iati y Heymondo, if we don't need insuranceWe'll grab him with... oh fat Globalfine which is much cheaper, in this case we use Iati.
Payment card/currency exchange: we always go with Revolut definitely.
Roaming: No there is.
Other destinations in California: 
