AT&T Mexico announced last week that its LTE network is now available to some 45 million customers across the country. It first opened this 4G network to only six cities last October, not long after it reportedly paid $4.4 billion to acquire Nextel Mexico and Iusacell. But this has now been upped to more than 40 municipalities throughout Mexico. In addition to all the major hubs, people in emerging tech locations like Aguascalientes, Puebla, and Mérida can now access AT&T’s network.

With plans to pump another $3 billion into its high-speed network in the country over the next three years now that the industry has opened up, this number is only expected to grow. The telecom hopes to potentially serve up to 75 million customers by the end of this year and push that to 100 million before the end of 2018, as it continues to cut into the market dominance of Carlos Slim’s América Móvil.

This precedes the upcoming sale of new 4G network bands in Mexico. Telecoms regulator Ifetel has cleared 700 MHz of spectrum to make way for a shared 4G network. And although the bid process was initially delayed last month due to overwhelming interest, some 80 MHz of spectrum — in what Rethink-Wireless called “the coveted midrange bands for LTE (1.7-2.1 GHz)” — will be awarded before the end of the year.

This infrastructure expansion all comes on top of expanded capabilities in the fascinating undersea-cable network that connects Mexico to the rest of the word.

There are several that reach the nation, notably the 10,000-kilometer Pan-American Crossing cable. Owned by Level 3, it stretches from Grover Beach in California (just north of Los Angeles) to Tijuana and Mazatlán on the Pacific coast of Mexico before continuing down to Costa Rica and Panama. And Level 3 isn’t just responsible for this undersea connection. In 2015, it also extended its long-haul network from Monterrey to McAllen, Texas.

The ARCOS undersea cable connecting Mexico with Florida and the rest of the Caribbean (via Submarine Cable Map)

Then there is the Caribbean connection. The ARCOS cable, first laid in 2001, connects the entire region in a loop that stretches from Miami to Cancun and Tulum in Mexico. It has another 20 touch points southward throughout Central America down to Cartagena, Colombia, and over to Venezuela before hitting Puerto Rico, the Dominican Republic, and the Bahamas.

Cancún has also long been serviced by the the Maya-1 cable, a joint venture between Verizon, AT&T, Tata Communications, Telmex, and a dozen other firms. But the newest cable to come to the beach community is the Carlos Slim-owned America Movil Submarine Cable System-1, which since being laid in 2014 has stretched nearly 18,000 kilometers from as far north as Jacksonville, Florida, all the way to Rio de Janiero in Brazil.

While few really consider the cables that allow them to watch Netflix or talk to their loves ones on Facetime, underwater connections are critical to tech startups, innovation, and overall economic growth in 2016.

Online news magazine Vox recently released a video explaining how the world’s deep sea cable network keeps us all connected and why they are so critical. “For speedy international [data] travel, undersea cables are still where companies like Facebook and Google place their bets,” says the video. “That’s because the best way to create The Cloud is still by going under the sea.”