Petersglocke (pronounced [ˈpeːtɐsˌɡlɔkə]; English: "[Saint] Peter's bell"), commonly referred to as Dicker Pitter (German: [ˈdɪkɐ ˈpɪtɐ]; Kölsch: Decke Pitter or Dekke Pitter, pronounced [ˈdekə ˈpitˑɐ] ; i.e. "Fat/Big Peter"), is the largest bell in Cologne Cathedral. It was cast in 1923 by Heinrich Ulrich in Apolda and hangs in the belfry of the south tower. With a weight of approximately 24,000 kilograms (53,000 lb), a clapper weighing about 700 kilograms (1,500 lb) and a diameter of 322 centimetres (10 ft 7 in), it is the second largest (horizontally mounted) freely swinging ringable bell in the world, after the bell of the People's Salvation Cathedral in Bucharest, Romania.

When the bell was cast in 1923, the bell-founder refused to take German marks as a payment because of the hyper-inflation. Instead the Cathedral Chapter paid 5,000 US dollars. The predecessor of the bell was the "Emperor's Bell" (orig. German: Kaiserglocke) or Gloriosa ("Glorious") of 1873 which at 27,180 kilograms (59,920 lb) was even heavier than the St. Peter's bell. In 1918 it was melted down, because of the poor sound quality and the inadequate tone. Its metal was used for war purposes. During its thirty-year life it had regularly been put out of service to attempt to fix the inappropriate sound. Because of this the bell was nicknamed Große Schweigerin, or "big silence".

In 1951, a 110 centimetres (3.6 ft) long crack appeared on the bell. It was welded in 1956 by the company Lachenmeyer from Nördlingen. After repairs, the bell received a new, lighter clapper (approx. 600 kilograms [1,300 lb]), and it was rotated approximately 20 degrees so that the clapper did not strike the damaged area.

On 6 January 2011, the clapper broke and dropped on the floor below. The four earthquake sensors in the cathedral registered it. As it could not be repaired, a new one was cast and was installed in December of the same year. It was later discovered that the accident happened because the clapper had not been correctly installed in the 1950s, thus increasing wear, which consequently led to material degradation.

The new clapper weighs approx. 600 kilograms (1,300 lb) and is 3.20 metres (10 ft 6 in) long. It was installed on 2 December 2011, and was first rung on 7 December 2011. The workers installed two new electric ringing engines (500 rpm), which harmonized with the new clapper. The old engines worked with 750 rpm.

In 2016, it was discovered that uneven striking of the clapper meant that the “Dicke Pitter” was no longer emitting its customary sound. The Cologne University of Applied Sciences and the cathedral construction authority developed a new mount. In addition, a new corrosion protection product was developed by Dörken MKS-Systeme.

The bell is only rung on special occasions and on solemnities. The declaration or death of an Archbishop of Cologne or of a Pope, as well as the investiture of a new archbishop also warrant tolling St. Peter. All bells of the cathedral rang on the eve of 28 March 1936, a Friedensappell ("peace appeal") of Hitler, which he made in Cologne due to the Reichstag elections. Likewise, the St. Petersglocke declared the end of World War II above the ruins of the city of Cologne in 1945, and in 1990 the reunification of Germany. As a rule, St. Petersglocke rings solo for ten minutes before all the others, which join in accordance with the general ringing ordinance. However, not all South Tower bells will be rung every time. For the Feast of the Immaculate Conception bells 1–6 are rung and for the Christmas Eve Vigil bells 1–3.

Date/Day	Time	Occasion
7 December	19:30	Pre-Ringing for the Solemnity of the Immaculate Conception of the Blessed Virgin Mary
8 December	09:35	Solemnity of the Immaculate Conception of the Blessed Virgin Mary (Sundays)
	18:05	Solemnity of the Immaculate Conception of the Blessed Virgin Mary (Weekdays)
24 December	19:15	Pre-Ringing for the Solemnity of the Nativity of the Lord on Christmas Eve
	23:05	Christmas Vigil on Christmas Eve (together with the Pretiosa and Speciosa)
25 December	09:35	Christmas Day
1 January	00:00	Pre-Ringing for the new Year (Full chimes)
5 January	19:30	Pre-Ringing for the Solemnity of the Epiphany of the Lord
6 January	09:35	Epiphany of the Lord/Three Kings' Day
Holy Saturday	≈23:15	Glory of Easter for the Easter Vigil (Full chimes)
Easter Sunday	09:35	Resurrection of the Lord
Eve of Ascension Day	19:30	Pre-Ringing for Ascension Day
Ascension Day	09:35	Solemnity of the Ascension of the Lord
Pentecost Eve	19:30	Pre-Ringing for the Solemnity of Pentecost
Pentecost	09:35	Solemnity of Pentecost
Eve of Corpus Christi	19:30	Pre-Ringing for the Solemnity of Corpus Christi
Corpus Christi	09:35	Solemnity of Corpus Christi
	Procession and Entrance of the Blessed Sacrament	Solemnity of Corpus Christi (rung solo)
28 June	19:30	Pre-Ringing for the High/Patronage Feast of St. Peter and Paul
29 June	09:35	High/Patronage Feast of St. Peter and Paul (Sunday)
	18:05	High/Patronage Feast of St. Peter and Paul (Weekdays)
31 October	19:30	Pre-Ringing on All Hallows Eve
1 November	09:35	All Hallows/All Saints' Day

• 
  On this image the damaged area from the crack can be seen to the left of the clapper
• 
  The Peter's bell with the broken clapper
• 
  The Peter's bell with the new clapper
• 
  The Peter's Bell without a clapper

50°56′28″N 6°57′26″E / 50.9411°N 6.9573°E / 50.9411; 6.9573