Monuments

Monument Upgrades increase the multiplier by (15+10 x Upgrade level) per Upgrade
 * The cost progression for monument after the first:

Cost = basic * 5 * Level

Example: Mighty Statue Level 5 toward 6   2k Stone * 5 * 5 = 50k Stone
 * The cost progression for upgrades after the first:

Cost = basic * Level * Level

Example: Tomb of gods Level 6 toward 7   5 Village * 6 * 6 = 180 Village