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FireChat is the perfect travel app, allowing users to send and receive text messages entirely without data or internet thanks to something called mesh networking.
Basically, mesh networking allows you to communicate wirelessly by bouncing your message from one phone equipped with FireChat (within 210 feet of you) to another via Wi-Fi or Bluetooth antennas.
If there aren't any connections nearby, messages are stored until they can be sent. And don't worry: Messages will be encrypted, so only the intended recipient will be able to read them. The message then keeps bouncing from phone to phone until it reaches said recipient - and to cross oceans, for example, it'll hop from phone to phone until it reaches one with internet, then making its way to its final destination like any other message.
Sure, this can take a few minutes - 10 to 20 across a dense metro area, according to Skift - but you'll be able to send texts from abroad without incurring roaming charges or even from remote or blackout areas that have little to no coverage, including planes and subways.
Of course, this means that the more people download the app the better: According to Skift, only about 5 million mobile users worldwide have downloaded the app, but the app's creators estimate that as long as 5% of a city's population has it, messages can be delivered in around 10 minutes.
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Originally designed for people to get in touch with each other at crowded events, FireChat became hugely popular in Iraq last year after the country faced restrictions on internet use, and it was an integral part of the 2014 Hong Kong protests and 2015 Ecuadorian protests.
While you may continue to use Facebook Messenger or WhatsApp when connected to the internet, what makes FireChat so great is that it doesn't rely on any carrier and will work anywhere.