<https://blog.walls.io/showcases/social-wall-integration-virtual-events/#primaryimage>
<http://schema.org/caption>
"A presenter is standing on a wide stage. There’s no audience in front of them. Behind them, there’s a projection of a video call screen with many participants. On the left, a sign says “National Geographic Storytellers Summit 2021”."
<https://blog.walls.io/showcases/social-wall-integration-virtual-events/>