diff --git a/40 Simple GUI Quiz/eiffel_tower.png b/40 Simple GUI Quiz/eiffel_tower.png
new file mode 100644
index 0000000..89404d7
Binary files /dev/null and b/40 Simple GUI Quiz/eiffel_tower.png differ
diff --git a/40 Simple GUI Quiz/landmark_icon.png b/40 Simple GUI Quiz/landmark_icon.png
new file mode 100644
index 0000000..80736e4
Binary files /dev/null and b/40 Simple GUI Quiz/landmark_icon.png differ
diff --git a/40 Simple GUI Quiz/landmark_quiz.py b/40 Simple GUI Quiz/landmark_quiz.py
new file mode 100644
index 0000000..a652b78
--- /dev/null
+++ b/40 Simple GUI Quiz/landmark_quiz.py	
@@ -0,0 +1,69 @@
+import tkinter as tk
+from tkinter import messagebox
+from pathlib import Path
+from PIL import Image, ImageTk
+
+ROOT = Path(__file__).resolve().parent
+
+root = tk.Tk()
+root.title("Landmark Quiz")
+root.geometry("600x560")
+root.resizable(False, False)
+
+# Load and resize landmark image
+image = Image.open(ROOT / "eiffel_tower.png")
+image = image.resize((300, 300))
+
+landmark = ImageTk.PhotoImage(image)
+
+# Window icon
+icon = tk.PhotoImage(file=ROOT / "landmark_icon.png")
+root.iconphoto(False, icon)
+
+title = tk.Label(root, text="Famous Landmark Quiz", font=("Arial", 20, "bold"))
+title.grid(row=0, column=0, columnspan=2, pady=(15, 10))
+
+picture = tk.Label(root, image=landmark)
+picture.grid(row=1, column=0, columnspan=2, padx=20, pady=10)
+
+question = tk.Label(
+    root,
+    text="Which city is this landmark situated in?",
+    font=("Arial", 13)
+)
+question.grid(row=2, column=0, columnspan=2, pady=8)
+
+entry = tk.Entry(root, width=30, font=("Arial", 12))
+entry.grid(row=3, column=0, columnspan=2, pady=8)
+entry.focus()
+
+result = tk.Label(root, text="", font=("Arial", 12))
+result.grid(row=5, column=0, columnspan=2, pady=10)
+
+def check_answer():
+    answer = entry.get().strip().lower()
+
+    if answer == "paris":
+        result.config(text="Correct! The Eiffel Tower is in Paris.")
+        messagebox.showinfo("Correct", "Well done! Paris is the correct answer.")
+        entry.delete(0, tk.END)
+    else:
+        result.config(text="That answer is incorrect. Try again.")
+        messagebox.showerror("Try again", "Incorrect. Please try again.")
+        entry.select_range(0, tk.END)
+        entry.focus()
+
+def clear_answer():
+    entry.delete(0, tk.END)
+    result.config(text="")
+    entry.focus()
+
+check_button = tk.Button(root, text="Check answer", command=check_answer, width=16)
+check_button.grid(row=4, column=0, padx=10, pady=5)
+
+clear_button = tk.Button(root, text="Clear", command=clear_answer, width=16)
+clear_button.grid(row=4, column=1, padx=10, pady=5)
+
+root.bind("<Return>", lambda event: check_answer())
+
+root.mainloop()
diff --git a/41 Complete the update feature/address_book.db b/41 Complete the update feature/address_book.db
new file mode 100644
index 0000000..83c094e
Binary files /dev/null and b/41 Complete the update feature/address_book.db differ
diff --git a/41 Complete the update feature/address_book.py b/41 Complete the update feature/address_book.py
new file mode 100644
index 0000000..41d9170
--- /dev/null
+++ b/41 Complete the update feature/address_book.py	
@@ -0,0 +1,215 @@
+import tkinter as tk
+from tkinter import ttk, messagebox
+import sqlite3
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent
+DB = ROOT / "address_book.db"
+
+root = tk.Tk()
+root.title("Address Book")
+root.geometry("620x620")
+root.resizable(False, False)
+
+def connect():
+    return sqlite3.connect(DB)
+
+def clear_entries():
+    f_name.delete(0, tk.END)
+    s_name.delete(0, tk.END)
+    mob.delete(0, tk.END)
+    email.delete(0, tk.END)
+
+def submit():
+    values = (
+        f_name.get().strip(),
+        s_name.get().strip(),
+        mob.get().strip(),
+        email.get().strip(),
+    )
+
+    if not all(values):
+        messagebox.showwarning("Missing data", "Please fill in all four fields.")
+        return
+
+    conn = connect()
+    c = conn.cursor()
+    c.execute(
+        """
+        INSERT INTO address_book (f_name, s_name, mob, email)
+        VALUES (?, ?, ?, ?)
+        """,
+        values,
+    )
+    conn.commit()
+    conn.close()
+
+    clear_entries()
+    search()
+
+def search():
+    conn = connect()
+    c = conn.cursor()
+    c.execute("""
+        SELECT f_name, s_name, mob, email, oid
+        FROM address_book
+        ORDER BY oid
+    """)
+    records = c.fetchall()
+    conn.close()
+
+    output.delete("1.0", tk.END)
+
+    if not records:
+        output.insert(tk.END, "No records found.")
+        return
+
+    for record in records:
+        output.insert(
+            tk.END,
+            f"OID: {record[4]} | "
+            f"{record[0]} {record[1]} | "
+            f"Mobile: {record[2]} | "
+            f"Email: {record[3]}\n"
+        )
+
+def delete_rec():
+    oid = id_no.get().strip()
+
+    if not oid.isdigit():
+        messagebox.showwarning("Invalid OID", "Enter a valid numeric OID.")
+        return
+
+    conn = connect()
+    c = conn.cursor()
+    c.execute("DELETE FROM address_book WHERE oid = ?", (int(oid),))
+    deleted = c.rowcount
+    conn.commit()
+    conn.close()
+
+    id_no.delete(0, tk.END)
+
+    if deleted:
+        messagebox.showinfo("Deleted", f"Record {oid} was deleted.")
+    else:
+        messagebox.showwarning("Not found", f"No record with OID {oid} exists.")
+
+    search()
+
+def update_rec():
+    oid = id_no.get().strip()
+    column = update_column.get()
+    value = update_value.get().strip()
+
+    allowed_columns = {
+        "First Name": "f_name",
+        "Surname": "s_name",
+        "Mobile": "mob",
+        "Email": "email",
+    }
+
+    if not oid.isdigit():
+        messagebox.showwarning("Invalid OID", "Enter a valid numeric OID.")
+        return
+
+    if not value:
+        messagebox.showwarning("Missing value", "Enter the new value.")
+        return
+
+    # The column name cannot be passed as a normal SQL parameter,
+    # so only a value from this fixed whitelist is allowed.
+    db_column = allowed_columns[column]
+
+    conn = connect()
+    c = conn.cursor()
+
+    sql = "UPDATE address_book SET {} = ? WHERE oid = ?".format(db_column)
+    c.execute(sql, (value, int(oid)))
+    updated = c.rowcount
+
+    conn.commit()
+    conn.close()
+
+    if updated:
+        messagebox.showinfo(
+            "Updated",
+            f"Record {oid} was updated successfully."
+        )
+        id_no.delete(0, tk.END)
+        update_value.delete(0, tk.END)
+        search()
+    else:
+        messagebox.showwarning(
+            "Not found",
+            f"No record with OID {oid} exists."
+        )
+
+# Create database/table if it does not already exist.
+conn = connect()
+c = conn.cursor()
+c.execute("""
+CREATE TABLE IF NOT EXISTS address_book (
+    f_name TEXT,
+    s_name TEXT,
+    mob TEXT,
+    email TEXT
+)
+""")
+conn.commit()
+conn.close()
+
+# ---------- GUI ----------
+tk.Label(root, text="First Name").grid(row=0, column=0, sticky="e", padx=8, pady=6)
+f_name = tk.Entry(root, width=35)
+f_name.grid(row=0, column=1, padx=8, pady=6)
+
+tk.Label(root, text="Surname").grid(row=1, column=0, sticky="e", padx=8, pady=6)
+s_name = tk.Entry(root, width=35)
+s_name.grid(row=1, column=1, padx=8, pady=6)
+
+tk.Label(root, text="Mobile").grid(row=2, column=0, sticky="e", padx=8, pady=6)
+mob = tk.Entry(root, width=35)
+mob.grid(row=2, column=1, padx=8, pady=6)
+
+tk.Label(root, text="Email").grid(row=3, column=0, sticky="e", padx=8, pady=6)
+email = tk.Entry(root, width=35)
+email.grid(row=3, column=1, padx=8, pady=6)
+
+tk.Button(root, text="Save", command=submit, width=14).grid(
+    row=4, column=0, padx=8, pady=10
+)
+tk.Button(root, text="Display all", command=search, width=14).grid(
+    row=4, column=1, sticky="w", padx=8, pady=10
+)
+
+tk.Label(root, text="Enter OID").grid(row=5, column=0, sticky="e", padx=8, pady=6)
+id_no = tk.Entry(root, width=35)
+id_no.grid(row=5, column=1, padx=8, pady=6)
+
+tk.Button(root, text="Delete", command=delete_rec, width=14).grid(
+    row=6, column=0, padx=8, pady=8
+)
+
+tk.Label(root, text="Update field").grid(row=7, column=0, sticky="e", padx=8, pady=6)
+update_column = ttk.Combobox(
+    root,
+    values=("First Name", "Surname", "Mobile", "Email"),
+    state="readonly",
+    width=32,
+)
+update_column.current(0)
+update_column.grid(row=7, column=1, padx=8, pady=6)
+
+tk.Label(root, text="New value").grid(row=8, column=0, sticky="e", padx=8, pady=6)
+update_value = tk.Entry(root, width=35)
+update_value.grid(row=8, column=1, padx=8, pady=6)
+
+tk.Button(root, text="Update", command=update_rec, width=14).grid(
+    row=9, column=0, columnspan=2, pady=8
+)
+
+output = tk.Text(root, width=72, height=13, wrap="word")
+output.grid(row=10, column=0, columnspan=2, padx=10, pady=12)
+
+search()
+root.mainloop()