Trench warfare is a type of land warfare using occupied fighting lines comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are sheltered from artillery. Trench warfare lasting for several years took place on the Western Front in World War I. Following that war, "trench warfare" became a byword for stalemate, attrition and futility in conflict. Trench warfare proliferated when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench and dugout systems opposing each other along a front, protected from assault by barbed wire; the area between opposing trench lines was exposed to artillery fire from both sides. Attacks if successful sustained severe casualties. With the development of armoured warfare and combined arms tactics, emphasis on trench warfare has declined, but it still occurs wherever battle lines become static.

Field works are as old as armies. Roman legions, when in the presence of an enemy, entrenched camps nightly when on the move. In the early-modern era troops used. For example: Members of the Grand Alliance built the Lines of Stollhofen at the start of the War of the Spanish Succession of 1702–1714; the works ran for about 15 km from Stollhofen on the Rhine to the impenetrable woods on the hills east of Bühl. They played a pivotal role in manoeuvring; the French demolished them. The French built the 19-kilometre-long Lines of Weissenburg during the War of the Spanish Succession under the orders of the Duke of Villars in 1706; these were to remain in existence for just over 100 years and were last manned during Napoleon's Hundred Days. By 1870 the Lines no longer existed, but the two central forts in the towns of Wissembourg and Altenstadt still possessed fortifications that proved useful defensive positions during the Battle of Wissembourg; the French built the Lines of Ne Plus Ultra during the winter of 1710–1711, which have been compared to the trenches of World War I.

They ran from Arras to Cambrai and Valenciennes where they linked up with existing defensive lines fronted by the river Sambre. In the 1711 campaign season the Duke of Marlborough breached them through "a magnificent piece of manoeuvring". During the Peninsular War, the British and Portuguese constructed the Lines of Torres Vedras in 1809 and 1810. Although Napoleon Bonaparte started his military career in artillery, campaigning in the Napoleonic Wars emphasized movement rather than static entrenchment, but innovations in trench warfare became more prominent in the course of the 19th century. In the New Zealand Wars, the indigenous Maori developed elaborate trench and bunker systems as part of fortified areas known as pā, employing them as early as the 1840s to withstand British cannon, an experimental poison-gas mortar; these systems included firing trenches, communication trenches and anti-artillery bunkers. British casualty rates of up to 45 percent, such as at Gate Pa in 1844 and the Battle of Ohaeawai in 1845, suggested that contemporary firepower was insufficient to dislodge defenders from a trench system.

There has been an academic debate surrounding this since the 1980s, when in his book The New Zealand Wars, historian James Belich claimed that Northern Māori had invented trench warfare during the first stages of the New Zealand Wars. However, this has been criticised by some other academics, with Gavin McLean noting that "Māori had adapted pā to suit the musket, but others dismissed Belich’s claim as baseless post-colonial revisionism."The Crimean War saw "massive trench works and trench warfare" though "the modernity of the trench war was not apparent to the contemporaries". North American armies employed field works and extensive trench systems in the American Civil War — most notably in the sieges of Vicksburg and Petersburg, the latter of which saw the first use by the Union Army of the rapid-fire Gatling gun, the important precursor to modern-day machine guns. Trenches featured in the Paraguayan War, the Second Anglo-Boer War, the Russo-Japanese War. Fundamentally, as the range and rate of fire of rifled small-arms increased, a defender shielded from enemy fire was able to kill several approaching foes before they closed with his position.

Attacks across open ground became more dangerous after the introduction of rapid-firing artillery, exemplified by the "French 75", high explosive fragmentation rounds. The increases in firepower had outstripped the ability of infantry to cover the ground between firing lines, the ability of armour to withstand fire, it would take a revolution in mobility to change that. Trench warfare became archetypically associated with the World War I, when the Race to the Sea expanded trench use on the Western Front starting in September 1914. By the end of October 1914, the whole front in Belgium and France had solidified into lines of trenches, which lasted until the last weeks of the war. Mass infantry assaults were futile in the face of artillery fire, as well as rapid rifle and machine-gun fire. Both sides concentrated on breaking up enemy attacks and on protecting their own troops

The Project 58181 Centaur class is a series of small armored assault craft being built for the Ukrainian Navy. The first two vessels were laid down at the Kuznya na Rybalskomu in December 2016; the project was developed by State Research and Design Shipbuilding Center on the basis of the Gyurza-M class artillery boats. Designed for carrying patrol service on rivers and coastal maritime areas and landing of marines; the project 58181 was developed by State Research and Design Shipbuilding Center on the basis of the Gyurza-M class artillery boats in 2015. However, it was refined during construction; the first contract was signed in 2016. On September 4, 2018, the first launching ceremony for the first boat of the first series was held; the boat was built on a revised project, which received new project number 58503 and the code «Centaur-LK». On September 20, the second boat of the series was launched. On November 19, 2018, newly built assault boats arrived to Odessa to continue testing; the top speed of 50 knots is achieved by a pair of New Zealand-made Hamilton Jet water jet propulsion engines and can stay at sea for a maximum of five days.

The class is armed with two remote weapon stations with 12.7 mm high-caliber machine guns and a 40-mm rocket launcher. The boats feature two 80-mm rocket-launch systems. Ukraine Ukrainian Navy: 2 On trial, 1 in order Project number 58503 «Centaur-LK» CB90-class fast assault craft Multipurpose Assault Craft List of active Ukrainian Navy ships Fast assault craft “Kentavr” at the State Research and Design Shipbuilding Center "Десантно-штурмовий катер проекту 58181". Www.ukrmilitary.com. Ukrainian Military Pages. 2017-11-24. Retrieved 2018-01-23

The effects of Hurricane Dorian in the Bahamas were among the worst experienced for any natural disaster in the country. Hurricane Dorian struck the Abaco Islands as a Category 5 hurricane on September 1, a day hit Grand Bahama Island at the same category; the hurricane stalled over Grand Bahama for another day pulling away from the island on September 3. Damage amounted to US$3.4 billion, there were at least 70 deaths in the country. Another 282 people were left missing after the hurricane; as early as August 26, the National Hurricane Center warned for the potential of then–Tropical Storm Dorian to affect the Bahamas within five days, noting uncertainty due to potential interaction with Hispaniola. By August 28, the NHC was forecasting for Dorian to pass near the northern Bahamas as a major hurricane. On August 30, the government of the Bahamas issued a hurricane watch, that day a hurricane warning, for the northwestern Bahamas, including the Abacos, Berry Islands, Eleuthera, Grand Bahama Island, New Providence.

A hurricane watch was issued for Andros Island. The advisory meant that hurricane conditions were within 48 hours; the warnings were downgraded after Dorian moved away from the country on September 3. Forced evacuations were issued for the Abacos and Grand Bahama on August 31 as Dorian intensified while tracking towards the Bahamas. In low-lying cays, government officials went from door to door urging residents to move inland. Skiffs rented by the Bahamian government shuttled residents of outlying fishing communities to McLean's Town in Grand Bahama. Most major resorts were forced to close. Nine hurricane shelters were opened on Grand Bahama and 15 shelters were opened on the Abacos; some chose to shelter at resorts instead, despite warnings by government officials that the buildings were unsafe. Prime Minister of the Bahamas Hubert Minnis warned people to "not be foolish and try to brave out this hurricane" adding that those that did not evacuate "are placing themselves in extreme danger and can expect a catastrophic consequence".

Airports in the Abacos, Grand Bahama, Bimini were closed by September 1. Government workers were ordered to stay indoors. On September 1, the eye of Hurricane Dorian made landfall on the Abaco Islands with maximum sustained winds of 185 mph, making it the strongest hurricane on record to affect the Bahamas. On September 2, the eye of Dorian moved over the eastern end of Grand Bahama Island, drifted across the island. Bahamian Minister of Agriculture Michael Pintard reported an estimated storm tide of 20 to 25 ft at his home on Grand Bahama. Dorian dropped an estimated 3.0 ft of rain over the Bahamas. Hurricane Dorian killed 10 on Grand Bahama. One of the fatalities was classified as indirect. Damage amounted to US$3.4 billion. Insured losses alone were confirmed to be at least US$1 billion. Across the Bahamas, the storm left at least 70,000 people homeless. An estimated 13,000 homes, constituting 45% of the homes on the Abacos and Grand Bahama, suffered severe damage or were destroyed. Hurricane Dorian knocked out the power, telecommunications, sewage service on the Abacos.

For several days, Marsh Harbour Airport on Great Abaco was underwater, the control tower was damaged by the waters. The airport was closed on September 4. About 90% of the infrastructure in Marsh Harbour was damaged; the shantytowns of Marsh Harbour, housing poor Haitian immigrants, were destroyed. In central and northern Abaco, Dorian damaged roadways, as well as thousands of houses, with 60% of homes in northern Abaco damaged or destroyed; the power grid serving the entirety of the Abacos was destroyed. The terminal building of Treasure Cay Airport suffered significant damage. There was an island-wide power outage on Grand Bahama Island, an oil refinery was damaged. About 300 homes on the island were destroyed or damaged, with the heaviest damage on the eastern side of the island. At least 60% of Grand Bahama Island was left submerged as Dorian moved away on September 3. Grand Bahama International Airport went underwater by 07:00 UTC September 2, with water levels reaching 6 ft. Strong winds at the airport damaged buildings and aircraft, leaving debris strewn across the airport and surrounding roads.

Floodwaters and sewage contaminated Rand Memorial Hospital. The operating room, intensive care unit, the wards were rendered unusable after being tainted by sewage, while mold outbreaks after the floodwaters receded forced more parts of the hospital to be evacuated; the two main supermarkets in Freeport, as well as their warehouses, were inundated by storm surge. At 11:24 UTC on September 2, 2019, total power was lost on the island of New Providence; the following day, by 1:50, 40% of power had been restored. The National Emergency Management Agency of the Bahamas handled the response to the hurricane, working with the Caribbean Disaster Emergency Management Agency. In the days after Dorian affected the Bahamas, officials surveyed the damage by air. Residents in the Abacos and Grand Bahama suffered from water shortages, power outages, a lack of telecommunications. After the storm, at least 2,000 people stayed in government shelters. Thousands of people left Abaco and Grand Bahama in the days after the storm, with the Department of Rehabilitative Welfare Services in New Providence recording 6,854 evacuees entering Nassau by air from September 5–13.

Several cruise companies redirected their ships to bring aid and transport passengers off the affected islands. Bahamasair offered free flights