Question: What do the films "Giuliani Time" and "Life After People" have in common?
Context: Petrus is a Latin name derived from the Greek meaning "rock", and is the common English prefix "petro-" used to describe rock-based substances, like petros-oleum or "rock oil."  As the source of Peter, it is a common name for people from antiquity through the medieval era.  In the Netherlands and South Africa it remained a very common given name, though in daily life, many use less formal forms like "Peter", "Pierre", "Piet" and "Pieter". Life After People is a television series on which scientists, structural engineers, and other experts speculate about what might become of Earth should humanity instantly disappear.  The featured experts also talk about the impact of human absence on the environment and the vestiges of civilization thus left behind.  The series was preceded by a two-hour special that aired on January 21, 2008 on the History Channel which served as a de facto pilot for the series that premiered April 21, 2009.  The documentary and subsequent series were both narrated by James Lurie. Gerald B. Lefcourt is a criminal defense lawyer with a reputation for taking on unpopular and high-profile clients, including such clients as the Black Panthers, Abbie Hoffman, Harry Helmsley, a co-defendant of Michael Milken, former New York State Assembly Speaker, Mel Miller, Russell Crowe, and Tracy Morgan.  He was a featured personality in the 2006 documentary Giuliani Time.  Recent victories include a full acquittal of rap mogul and Murder, Inc.  Records founder Irv Gotti on federal money laundering charges.  Lefcourt is currently one of the attorneys in the federal KPMG tax shelter fraud prosecution, believed to be the largest tax fraud case ever brought in the history of the United States. A Common Word between Us and You is an open letter, dated 13 October 2007, from leaders of the Islamic religion to leaders of the Christian religion.  It calls for peace between Muslims and Christians and tries to work for common ground and understanding between both religions, in line with the Qur'anic commandment to "Say: 'O People of the Scripture!  come to a common word as between us and you: that we worship none but God'" and the Biblical commandment to love God, and one's neighbour.  In the time since its release, "A Common Word" opened an interfaith dialogue between Christians and Muslims.  In 2008 the initiative was awarded the "Eugen Biser Award", and the "Building Bridges Award" from the UK's Association of Muslim Social Scientists. A commune (the French word appearing in the 12th century from Medieval Latin "communia", meaning a large gathering of people sharing a common life; from Latin "communis", things held in common) is an intentional community of people living together, sharing common interests, often having common values and beliefs, as well as shared property, possessions, resources, and, in some communes, work, income or assets. Giuliani Time is a 2005 documentary film by Kevin Keating about Rudy Giuliani, former Mayor of New York City. BookWars is an award-winning independent film from New York City by Jason "Jack RO" Rosette  produced by Camerado, about the life and times of New York City street booksellers.  Made on an ultra-low budget in a jazzy, impressionistic style reminiscent of the films of Robert Frank and poetry of the Beat Generation, "BookWars" is the only first-person documentary made during then-New York City Mayor Rudolph Giuliani's controversial "Quality of Life" campaign, which sought to limit and control individuals engaged in informal economic activities on the streets of New York City. Evidence of common descent of living organisms has been discovered by scientists researching in a variety of disciplines over many decades, demonstrating the common descent of all life on Earth developing from a last universal common ancestor.  This evidence constructs the theoretical framework on which evolutionary theory rests, demonstrates that evolution does occur, and is able to show the natural processes that led to the emergence of Earth's biodiversity.  Additionally, this evidence supports the modern evolutionary synthesis—the current scientific theory that explains how and why life changes over time.  Evolutionary biologists document evidence of common descent by developing testable predictions, testing hypotheses, and constructing theories that illustrate and describe its causes. Irritable bowel syndrome (IBS) is a group of symptoms—including abdominal pain and changes in the pattern of bowel movements without any evidence of underlying damage.  These symptoms occur over a long time, often years.  It has been classified into four main types depending on whether diarrhea is common, constipation is common, both are common, or neither occurs very often (IBS-D, IBS-C, IBS-M, or IBS-U respectively).  IBS negatively affects quality of life and may result in missed school or work.  Disorders such as anxiety, major depression, and chronic fatigue syndrome are common among people with IBS. "The Thresher's Labour" is one of three poems written by a common worker, Stephen Duck in 1730.  The poem is a description of Duck's struggles as an agricultural labourer, and a representation of the working class in general.  H. Gustav Klaus said it was the most accurate description of working life in verse, and praised Duck's recognition that work deserved a literary treatment.  "The Thresher's Labour" became the voice, in a sense, for the rural labourers who were oppressed.  It also became a model for other common labourers to follow as many other common workers began to write about their lives and their daily experiences.  It was the start of a new genre of literature developed by working-class people.
Answer: documentary film