An escape tunnel underneath the Berlin Wall has been opened to the public for the first time amid celebrations of the 30-year anniversary of the opening of East Germany's border.

The tunnel at Bernauer Strasse, near the main Wall memorial, was opened Thursday by Mayor Michael Mueller. He thanked those who started digging the 100-meter-long (yards) tunnel in late 1970, nine years after communist East Germany sealed its border.

The tunnel was built by a group of people who had escaped earlier to West Berlin. They wanted to help friends and family to flee to the West but, days before it was finished, East German officials discovered the tunnel and partially destroyed it.

Mueller said: "It's great to see that the battle for freedom was also taken underground."