Abstract: A modular play structure for animals positionable upon a support surface, comprising a base engageable with the support surface, a plurality of elongated spacer members, with each member having opposing ends. The plurality of spacer members are releasably attached end to end to adjacent spacer members in a linear configuration to form an elongated pole having two opposite ends. The interconnection of the adjacent ends spacer members forms a threaded connector assembly. One end of the pole is releasably attached to the base to support the pole in a vertical orientation relative to the base and the support structure. The pole and base together form a base unit. A structural piece is attachable between two spacer members to act as a platform to support a cat. The base units can be interconnected by structural pieces.