diff --git a/data/day_12.txt b/data/day_12.txt
new file mode 100644
index 0000000..c2b0b8d
--- /dev/null
+++ b/data/day_12.txt
@@ -0,0 +1,22 @@
+ax-end
+xq-GF
+end-xq
+im-wg
+ax-ie
+start-ws
+ie-ws
+CV-start
+ng-wg
+ng-ie
+GF-ng
+ng-av
+CV-end
+ie-GF
+CV-ie
+im-xq
+start-GF
+GF-ws
+wg-LY
+CV-ws
+im-CV
+CV-wg
diff --git a/src/day_12.jl b/src/day_12.jl
new file mode 100644
index 0000000..9170efd
--- /dev/null
+++ b/src/day_12.jl
@@ -0,0 +1,43 @@
+include(joinpath(readchomp(`git rev-parse --show-toplevel`), "aoc.jl"))
+import .Aoc: @aoc
+using Pipe: @pipe
+
+function visit(map, curr_cave, visited)
+	curr_cave == "end" ? (return 1) : nothing
+	curr_cave[begin] in 'a':'z' && curr_cave ∈ visited ? (return 0) : nothing
+
+	v = copy(visited)
+	push!(v, curr_cave)
+	return sum([ visit(map, e, v) for e in map[curr_cave] ])
+end
+
+function visit2(map, curr_cave, visited, d)
+	curr_cave == "end" ? (return 1) : nothing
+	curr_cave == "start" && length(visited) != 0 ? (return 0) : nothing
+	if curr_cave[begin] in 'a':'z' && curr_cave ∈ visited
+		d == nothing ? (d = curr_cave) : (return 0)
+	end
+	v = copy(visited)
+	push!(v, curr_cave)
+	return sum([ visit2(map, e, v, d) for e in map[curr_cave] ])
+end
+
+function prepare_input(input)
+	map = Dict()
+	for l in input
+		a, b = split(l, "-")
+		!haskey(map, a) ? (map[a] = [b]) : (push!(map[a], b))
+		!haskey(map, b) ? (map[b] = [a]) : (push!(map[b], a))
+	end
+	return map
+end
+
+function p1(input::Vector{String})
+	return visit(prepare_input(input), "start", [])
+end
+
+function p2(input::Vector{String})
+	return visit2(prepare_input(input), "start", [], nothing)
+end
+
+@aoc(2021, 12)