diff --git a/solution/85/main.go b/solution/85/main.go
new file mode 100644
index 0000000..351169e
--- /dev/null
+++ b/solution/85/main.go
@@ -0,0 +1,32 @@
+package main
+
+func maximalRectangle(matrix [][]byte) int {
+    heights := make([]int, len(matrix[0]) + 1)
+    heights[len(heights)-1] = -1
+    mx := 0
+    for _, row := range matrix {
+        for i := range row {
+            if row[i] == '1' {
+                heights[i]++
+            } else {
+                heights[i] = 0
+            }
+        }
+
+        stack := []int{}
+        for i, currentHeight := range heights {
+            for len(stack) > 0 && heights[stack[len(stack)-1]] > currentHeight {
+                prev := heights[stack[len(stack)-1]]
+                stack = stack[:len(stack)-1]
+
+                width := i
+                if len(stack) > 0 {
+                    width = i - stack[len(stack)-1] - 1
+                }
+                mx = max(mx, prev * width)
+            }
+            stack = append(stack, i)
+        } 
+    }
+    return mx
+}