diff --git a/data/day_11.txt b/data/day_11.txt
new file mode 100644
index 0000000..95f25a9
--- /dev/null
+++ b/data/day_11.txt
@@ -0,0 +1,10 @@
+4781623888
+1784156114
+3265645122
+4371551414
+3377154886
+7882314455
+6421348681
+7175424287
+5488242184
+2448568261
diff --git a/src/day_11.jl b/src/day_11.jl
new file mode 100644
index 0000000..f9fbffd
--- /dev/null
+++ b/src/day_11.jl
@@ -0,0 +1,78 @@
+include(joinpath(readchomp(`git rev-parse --show-toplevel`), "aoc.jl"))
+import .Aoc: @aoc
+using Pipe: @pipe
+using Combinatorics
+
+
+function step(map, copy, x, y)
+	level = copy[x][y] = map[x][y] + 1
+	if level == 10
+		global flahes = flashes + 1
+		for (x,y) in zip([-1,0,1,-1,1,-1,0,1], [1,1,1,0,0,-1,-1,-1])
+			if x in 1:length(map) && y in 1:length(map[1])
+				step(map, copy, x, y)
+			end
+		end
+	end
+end
+
+function solve(input, part)
+	map = [ parse.(Int, collect(l)) for l in input ]
+	elements = length(map) * length(map[1])
+	sum = 0
+	step = 0
+
+	while true
+		step += 1
+		flash = []
+		flashed = []
+		for x in 1:length(map)
+			for y in 1:length(map[1])
+				map[x][y] += 1
+				if map[x][y] > 9
+					push!(flash, [x,y])
+					push!(flashed, [x,y])
+				end
+			end
+		end
+		while length(flash) != 0
+			x, y = pop!(flash)
+			for (i,j) in zip([-1,0,1,-1,1,-1,0,1], [1,1,1,0,0,-1,-1,-1])
+				nx = x + i
+				ny = y + j
+				if nx in 1:length(map) && ny in 1:length(map[1])
+					map[nx][ny] += 1
+					if map[nx][ny] > 9 && [nx, ny] ∉ flashed
+						push!(flash, [nx,ny])
+						push!(flashed, [nx,ny])
+					end
+				end
+			end
+		end
+
+		for (x,y) in flashed
+			map[x][y] = 0
+		end
+
+		sum += length(flashed)
+
+		if part == 1 && step == 100
+			break
+		end
+
+		if part == 2 && length(unique(flashed)) == elements
+			return step
+		end
+	end
+	return sum
+end
+
+function p1(input::Vector{String})
+	solve(input, 1)
+end
+
+function p2(input::Vector{String})
+	solve(input, 2)
+end
+
+@aoc(2021, 11)