When you level up in Atlantica before level 59, you may smoothly level up. However there is a steep grind at level 59-66 compared to other ones in Atlantica. And the following is some information for you to upgrade. Have a look and you can obtain knowledge about Atlantica leveling.

Level 59-66 (Hanging Gardens of Babylon):
For the first time in a while, you will encounter some easy enemies with one or two exceptions. Almost any enemies here are good for farming this game. With the exception of the Keysha enemies, you'd better use the Slave mobs. They're relatively weak but still give decent experience and drops. Most of the enemies here are fairly weak and worth training on.

The first mini boss here is the Iron Doll Reaper and it only appears in the entrance area. It attacks like an axe, which means your entire row could be dead in a few hits. So you couldn’t ignore such serious problem. The second one here is like a giant Lionman. They tend to drop a Secret Material Chest. It is something that lets you pick from either Growth Vials or Mandragora. The Growth Vials may be much useful to you in the long run, while there are also some players pay Atlantica Online gold for that. 

The Prophet quest does not begin until level 70 so in order to obtain it you will need to revisit here later. The boss here (Tiamat) is fairly tough as well. You'd better get Osiris gear or Judgment scrolls before coming back for a serious fight with it. It can attack an entire column and has a powerful area skill as well.