5 charts that help explain Airbnb's rise from spare-room startup to $31 billion travel behemoth

• Airbnb has fundamentally changed the way many people travel by bringing home sharing into the mainstream.
• The company, last valued at $31 billion in 2017, has grown to rival the hotel industry, but competition is getting stiffer.
• Here are 5 charts that help explain the rise and evolution of Airbnb over the past several years.
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Airbnb has gone from renting out a single air mattress to a marketplace of more than seven million short-term rental properties across 220 countries in just over a decade.

The global travel company has acquired more than two dozen companies, received a private valuation of $31 billion, and has said it plans to go public in 2020.

Along the way, it has played a key role in popularizing home-sharing, produced countless entrepreneurs and competitors, fueled related industries like short-term rental insurance, and taken on a half-trillion-dollar hotel industry. Airbnb has also been met with backlash as it has become linked to escalating rent prices, exacerbating housing shortages, and controversy over how it handles fraud and deaths at the properties on its platform.

The company has also become more popular with professional property management companies as it has expanded into business travel. As short-term rental management has become an industry of its own, Airbnb has faced criticism from some who argue that its properties are essentially unregulated hotels and that the company has been overly aggressive in fighting cities' efforts to regulate it.

Airbnb has shaped the rental industry. Here are five charts that help explain its rise and impact on the way we travel.