What did Jacob see in his dream at Bethel?

Answer: Angels on a ladder

Jacob dreamed of a ladder reaching to heaven with God's angels going up and down on it; he named the place Bethel.

“And Jacob had a dream about a ladder that rested on the earth with its top reaching up to heaven, and God’s angels were going up and down the ladder. and he called that place Bethel, though previously the city had been named Luz.”— Genesis 28:12, 28:19 (BSB)