This expansion is pretty unique in that each player has an additional pawn, the Archaeologist, that can be moved around the landscape you are creating by using the routes you have placed by spending Action points. Your goal is to place sets of different kinds of Monuments (Arch, Temple, Tower) when you find archaeological sites.

You have 3 "Action points" to spend each round, and you can gain additional ones by foregoing the use of a Placement tile in the Active zone that round. You can spend 1 Action Point to either move the Archaeologist to an adjacent tile connected by Highway or, if the tile where the Archaeologist is contains a Station, more them to another tile containing a Station connected to the starting one by Railway. When the Archaeologist is on a tile containing an empty Monument pin point, you can also spend 1 Action Point to place a Monument pawn of the indicated type on that pin point.

Monument pawns don't score you points when you place them, but at the end of the game, you gain 1 point for each Monument pawn you have + 3 points for each complete set of 3 different Monument pawns (Arch, Temple, Tower) on your tiles.

Additionally, the Monuments Expansion comes with a few Objectives as well: for example, the Museum wants the Archaeologist to be on or around it at the end of the game, while the Castle must have at least 2 Towers around it.

—description from the publisher