Malta occupies 316 square kilometers in the central Mediterranean Sea, positioned 93 kilometers south of Sicily and 288 kilometers north of the Libyan coast. The archipelago comprises three inhabited islands: Malta at 246 square kilometers, Gozo at 67 square kilometers, and Comino at 3.5 square kilometers. Four uninhabited islets complete the territory: Filfla, St. Paul's Islands, Fungus Rock, and Fliegu. No point in the archipelago rises above 253 meters, a maximum elevation reached at Dingli Cliffs on the western coast of Malta island. The entire landmass rests on a sedimentary platform of Oligocene and Miocene limestone deposited between 33 million and 5 million years ago, creating a geology that determines every aspect of the visible landscape.
The rock foundation consists primarily of Lower Coralline Limestone, Globigerina Limestone, Blue Clay, Greensand, and Upper Coralline Limestone arranged in horizontal strata. This layered structure produces the terraced topography visible across all three inhabited islands, where harder limestone beds form vertical cliffs above receding slopes of softer globigerina and clay. The globigerina layer, named for the fossilized plankton shells compressed within it, provides the honey-colored building stone that defines Maltese architecture from Neolithic temples to contemporary construction. Upper Coralline Limestone, the youngest and hardest formation, creates the dramatic coastal cliffs along western and southern shorelines. Quarrying has extracted limestone continuously for 7,000 years, leaving abandoned excavation sites that now function as natural amphitheaters and water collection basins.
Water scarcity dominates the environmental reality of Malta. No permanent rivers or lakes exist anywhere in the archipelago. Annual rainfall averages 553 millimeters, falling almost entirely between October and March. Three ephemeral streams—Wied il-Kbir, Wied il-Għasel, and Wied il-Mielaħ—carry surface flow only after substantial rain events, typically fewer than 20 days per year. The porous limestone absorbs most precipitation immediately, creating a freshwater lens floating atop saline groundwater beneath the island. Historical reliance on this aquifer depleted it by the mid-20th century, introducing seawater intrusion that rendered much groundwater undrinkable. By 2024, reverse osmosis plants produce approximately 60 percent of Malta's potable water supply, with the Pembroke facility alone generating 120,000 cubic meters daily. The absence of surface water eliminates riparian vegetation, wetland ecosystems, and the wildlife communities dependent on them.
Dingli Cliffs form a 3-kilometer limestone escarpment along Malta's southwestern coast, dropping vertically to the sea from elevations between 220 and 253 meters. The Upper Coralline Limestone forming these cliffs erodes at approximately 1 to 2 millimeters annually through salt weathering and wave action at the base. Fossil records within the cliff face include echinoids, bivalves, and coralline algae from the Miocene epoch, visible in cross-section where rockfalls expose fresh surfaces. The clifftop plateau supports garrigue vegetation including Mediterranean thyme, sea squill, and prickly pear cactus introduced from the Americas in the 18th century. Agricultural terracing extends to within 50 meters of the cliff edge in some locations, stone-walled plots cultivating carobs, figs, and vegetables in the shallow topsoil. No barriers prevent access to the cliff edge, which experiences several fatal falls annually.
Comino's Blue Lagoon occupies a shallow basin between Comino's northern coast and the small islet of Cominotto. Water depth ranges from 1 to 3 meters across most of the lagoon, with a sandy bottom of crushed shell and limestone particles creating the visible turquoise coloration. The color results from selective light absorption: longer red wavelengths penetrate the shallow water and are absorbed by the pale substrate, while shorter blue wavelengths reflect back to observers. Peak summer days bring between 3,000 and 5,000 visitors to a beach area of approximately 3,000 square meters, a density that eliminates most marine vegetation and disturbs sediment continuously. Winter transforms the lagoon into an empty inlet with frequent wave action from northwestern storms. Posidonia oceanica seagrass meadows once extended throughout the lagoon but disappeared by the 1990s due to anchoring damage and sedimentation, leaving only isolated patches on the seaward perimeter.
Gozo presents more pronounced topography than Malta, with steeper valleys and a more dissected terrain despite lower maximum elevation. The island's highest point reaches 190 meters at Ta' Dbieġi. Dwejra Bay on Gozo's western coast contained the Azure Window, a natural limestone arch spanning 28 meters that collapsed into the sea on March 8, 2017, after sustained erosion weakened its load-bearing capacity. The arch formed through differential erosion of soft Globigerina Limestone beneath harder Upper Coralline Limestone, a process visible in other coastal features along the same bay. The Inland Sea at Dwejra connects to open water through a tunnel approximately 80 meters long carved through the headland, creating a circular pool 30 meters in diameter sheltered from wave action. Fungus Rock, a 60-meter-high limestone stack in Dwejra Bay, supported Cynomorium coccineum, a parasitic plant harvested from the 16th through 19th centuries for purported medicinal properties, though overharvesting eliminated the population.
Malta's coastline measures 196.8 kilometers, incorporating 157 kilometers of rocky shore, 32 kilometers of low-lying rock platforms, and only 7.8 kilometers of sandy beach. The Blue Grotto near Żurrieq comprises six sea caves carved into vertical cliffs at the waterline, with the largest extending 43 meters into the headland. Underwater visibility in calm conditions reaches 30 meters, allowing observation of the cave floors at depths between 5 and 15 meters. The blue illumination results from sunlight entering submerged cave mouths and reflecting off the white sandy bottom, projecting upward onto the limestone ceiling. Traditional luzzu fishing boats operate tours during calm weather between April and October, a period when westerly swells typically prevent safe entry. Winter storm waves can reach 4 meters at the cave entrances, making approach impossible for weeks consecutively.
Ramla Bay on Gozo's northern coast provides the archipelago's largest natural sand beach, extending 350 meters along a northwest-facing shoreline. The distinctive red-orange sand derives from iron oxide staining of limestone particles mixed with shell fragments, visible in individual grains under magnification. Beach depth from shoreline to backshore vegetation measures approximately 40 meters at the widest point, varying seasonally as winter storms remove sand that returns during calmer summer months. The Roman villa beneath the western headland, partially excavated in 1910, confirms human use of this bay for at least 2,000 years. Modern amenities remain minimal: a single seasonal refreshment outlet, portable toilets from May through September, and no permanent structures except an access road completed in 1968.
Mellieħa Bay on Malta's northern coast offers the island's longest stretch of continuous sand at 800 meters, facing north-northeast into a shallow embayment. Water depth increases gradually, reaching 2 meters approximately 50 meters from shore, making this the archipelago's only beach where children can wade substantial distances safely. The sand composition matches typical Mediterranean beaches: quartz grains, bioclastic fragments of shells and coral, and limestone particles eroded from the surrounding geology. Posidonia oceanica meadows begin at the 4-meter depth contour, extending northward along the seabed to approximately 30 meters depth. Summer temperatures in the shallow water reach 28°C by August, while winter lows drop to 14°C in February. Development surrounds the entire bay: hotels occupy the eastern headland, apartment buildings line the coastal road, and boat storage facilities cover the western end.