A ring of coastal mountains surrounds low central plains. The highest peak is Carrauntuohill (Irish: Corrán Tuathail), which is 1041 m (3414 feet). The island is bisected by the River Shannon, at 113 km (70 mi) the longest river in Ireland or Britain. The island's lush vegetation, a product of its mild climate and frequent but soft rainfall, earns it the sobriquet "Emerald Isle".
The Constitution of Ireland guarantees the rights of the family and the institution of marriage. However, the reality is that social and economic change in recent years has brought about significant changes in family life in the Republic. According to figures published in September, 2004, 31% of all births in the Republic of Ireland occur outside marriage. This compares with 5% in 1980. The average of mothers having their first child was 30 and the fertility is an average of 1.98 children.
A significant recent change to pub culture in Ireland has been the introduction of a smoking ban, in all workplaces, which includes pubs and restaurants. The ban was introduced on 29 March 2004. A majority of the population support the ban, including a significant percentage of smokers. Nevertheless, the atmosphere in pubs has changed greatly as a result, regardless of whether it has boosted or lowered sales, or whether it is a "good thing" or a "bad thing".
The area now known as Northern Ireland has had a diverse history. From serving as the bedrock of Irish resistance in the era of the plantations of Queen Elizabeth and James I in other parts of Ireland, it became itself the subject of major planting of Scottish and English settlers after the Flight of the Earls in 1607 (when the native aristocracy left en masse).
Northern Ireland has been a major factor in Irish politics since the island of Ireland was divided between Northern Ireland and the twenty-six county southern state in 1920. The creation of Northern Ireland led to conflict between northern nationalists (mostly Catholic) who seek unification with the independent southern state and Unionists (mostly Protestant) who wish for Northern Ireland to remain within the United Kingdom. This conflict exploded into a violent conflict in the late sixties known as the 'Troubles' involving groups such as the Provisional IRA, loyalist paramilitaries, the police and the British army. The Troubles have caused thousands of deaths in Northern Ireland but have also spilled over into bombings and acts of violence on Great Britain and in the Republic of Ireland.
In recent decades the Catholic population has increased in percentage terms within Northern Ireland, while the Presbyterian and Church of Ireland population percentages have decreased. However the decreasing size of Catholic families and the increasing use of birth control among the Catholic community and led to a slowing down in the growth of the Catholic population. Statisticians predict both communities will achieve close to parity in size, with Protestants dominant primarily to the east of Northern Ireland and Catholics dominant to the west and south. However as of 2005 most statisticians predict that Protestants will continue to slightly outnumber Catholics in Northern Ireland as a whole. As not all Catholics are nationalists, they predict a continuing majority in favour of the union with the United Kingdom. However this is disputed by a minority of statisticians.
Executive authority is exercised by a cabinet known simply as the Government. The Government consists of the Taoiseach (prime minister), the Tánaiste (deputy prime minister) and up to thirteen other ministers. The Taoiseach is appointed by the President, after being designated by Dáil Éireann (the lower house of parliament). The remaining ministers are nominated by the Taoiseach and approved by the Dáil. The Government must enjoy the confidence of Dáil Éireann and, in the event that they cease to enjoy the support of the lower house, the Taoiseach must either resign or persuade the President to dissolve the Dáil, in which case a general election follows.
There have been recent efforts in Ireland to use renewable energy such as wind energy with large wind farms being constructed in coastal counties such as Mayo and County Antrim. Recently what will be the world's largest offshore wind farm is being developed at Arklow Bank off the coast of Wicklow. It is estimated to generate 10% of Irelands energy needs when it is complete. These constructions have in some cases been delayed by opposition from locals, most recently on Achill Island, some of whom consider the wind turbines to be unsightly. Another issue in the Republic of Ireland is the failure of the aging network to cope with the varying availability of power from such installations. Turlough Hill is the only energy storage mechanism in Ireland.
From its creation in 1921 until 1972 Northern Ireland enjoyed limited self-government within the United Kingdom, with its own parliament and prime minister. However the Protestant and Catholic communities in Northern Ireland each voted almost entirely along sectarian lines, meaning that the government of Northern Ireland was dominated by the Unionist majority which did not permit Catholics to participate in the government.
Under the Belfast Agreement (also known as the Good Friday Agreement) and Article 3 of the constitution a North-South Ministerial Council and six North-South Implementation Bodies coordinate activities and exercise a limited governmental role within certain policy areas across the whole island of Ireland. The Implementation Bodies have limited executive authority in six policy areas. Meetings of the Council take the form of meetings between ministers from both the Republic's Government and the Northern Ireland Executive.
Northern Ireland was covered by an ice sheet for most of the last ice age and on numerous previous occasions, the legacy of which can be seen in the extensive coverage of drumlins in Counties Fermanagh, Armagh, Antrim and particularly Down. The centrepiece of Northern Ireland's geography is Lough Neagh, at 392 km² the largest freshwater lake in the British Isles. A second extensive lake system is centred on Lower and Upper Lough Erne in Fermanagh.
Since its foundation it has been the stated long-term policy of governments of the state now called the Republic of Ireland to bring an end to the conflict in Northern Ireland and to bring about a united Ireland. Northern Ireland has also, in the past, often been a source of conflict between the Irish Government and the government of the United Kingdom. In order to find a solution to the Troubles the Irish Government became a partner in the Good Friday (Belfast) Agreement in 1998.
Today, Northern Ireland comprises a diverse patchwork of community rivalries, represented in some areas by whole communities where lamp posts and some homes fly the Irish national flag, the tricolour, or the Union Flag, the symbol of British identity, while even the kerbstones in less affluent areas get painted green-white-orange or red-white-blue, depending on whether a local community expresses nationalist/republican or unionist/loyalist sympathies.