Tree of Knowledge
Tree of Knowledge is an adventure map object which boosts every hero who visits up to the next level, once.
More accurately, it gives your hero the maximum amount of experience needed to gain a level. For example, let's say you have a hero at Level 7. The experience cutoff for Level 7 is 8,000, and the cutoff for Level 8 is 10,000. If your hero has 9,000 experience and visits a Tree of Knowledge, he'll end up with 11,000 experience, since the tree gives you enough experience to level you from the cutoff to the next cutoff, no matter how much experience your hero actually has. As a consequence, it is no better to visit the Tree of Knowledge immediately after gaining a level as compared to being 1 EXP away from the next level. However, the higher your current level, the greater the gap between cutoffs, and the more experience you end up getting from the tree. It can therefore be beneficial to stave off using a tree near your castle for a couple of levels.
Levelling up may cost either 2000 Gold, 10 Gems or nothing.
There can no more than 32 Trees of Knowledge on one map.