Gruta Rei do Mato is the headline sight in Sete Lagoas: a limestone cave with guided access through chambers of stalactites, stalagmites, and rare parallel columns. The main visited route is short enough for a relaxed stop, but the scale of the formations gives it real weight.
A smaller cave nearby has prehistoric rock paintings, which helps make the visit feel less like a simple geology stop. The cave sits near BR-040, so it is also the easiest Sete Lagoas attraction to fold into a trip from Belo Horizonte.