Volodymyr Bondarenko spends most of the day locked in his apartment in Kiev, Ukraine. As he listens to air strike sirens and exchanges messages with family, he communicates with a host of Airbnb guests booking his one-room apartment for rent in the heart of Ukraine's capital.

Sometimes, he sends an emoji crying, CNN reports. Other times, an emoji of praying hands. It's his way of thanking those who are booking the apartment - even though they have no plans to visit the house.

People around the world are booking apartments and rooms on Airbnb as part of a social media campaign to send money to Ukrainians.

The idea has been embraced by many people. CNN reports that on March 2 and 3, people from all over the world booked more than 61,000 nights in Ukraine, according to an Airbnb spokesman. More than half of those nights were booked by the Americans, he said.

Campaign organizers are also urging people to make sure rents are operated by individuals rather than companies.