What do toi think Annabeth's 4th and 5th beads might be?

Beads we know:
1. Thalia's arbre
2. A centaur in a prom dress
3. A greek trireme (that was a kind of bateau with three rows of oars)
After she told Percy about these first three, he interrupted her, so beads 4, and 5 were is still unknown.
6. A trident from Percy's first year.
7. Thalia's arbre with the Golden Fleece was the bead for Percy's seconde year.
8. The suivant bead was the labyrinth.
9. Empire State Building with silver swirls and the names of all the campers who died in the war