diff --git a/0221-Maximal-Square.py b/0221-Maximal-Square.py
new file mode 100644
index 0000000..1d45de8
--- /dev/null
+++ b/0221-Maximal-Square.py
@@ -0,0 +1,43 @@
+'''
+Given a 2D binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area.
+
+Example:
+
+Input: 
+
+1 0 1 0 0
+1 0 1 1 1
+1 1 1 1 1
+1 0 0 1 0
+
+Output: 4
+'''
+class Solution:
+    def maximalSquare(self, matrix: List[List[str]]) -> int:
+        
+        rows, cols = len(matrix), len(matrix[0]) if len(matrix) else 0
+        length = [0] * (cols + 1)
+        max_len = prev = 0
+        
+        for i in range(1, rows + 1):
+            
+            for j in range(1, cols + 1):
+                
+                temp = length[j]
+                
+                if matrix[i - 1][j - 1] == '1':
+                    
+                    if length[j - 1] < prev:
+                        length[j] = length[j - 1] if length[j - 1] < length[j] else length[j]
+                    
+                    else:
+                        length[j] = prev if prev < length[j] else length[j]
+                    
+                    length[j] += 1
+                    max_len = length[j] if length[j] > max_len else max_len
+                
+                else: length[j] = 0
+                
+                prev = temp
+        
+        return max_len * max_len