See you in the morning

"See you in the morning. Make sure you’re not late," my grandfather said. Then, he handed me this photo and left. I was worried I wouldn’t be able to solve my grandfather’s puzzle, so I immediately set my attention to it. Late into the evening, I was struggling still and thought I would need to call him and sheepishly ask for an explanation.

Then, I had a simple idea. I grabbed a World Book Encyclopedia and set to work. Just a minute later and I knew exactly what time to meet my grandfather.

What time was I supposed to meet him?