Ngorongoro District in the context of "Karatu District"

The Olduvai Gorge or Oldupai Gorge in Tanzania is one of the most important paleoanthropological localities in the world; the many sites exposed by the gorge have proven invaluable in furthering understanding of early human evolution. A steep-sided ravine in the Great Rift Valley that stretches across East Africa, it is about 48 km (30 mi) long, and is located in the eastern Serengeti Plains within the Ngorongoro Conservation Area in the Olbalbal ward located in Ngorongoro District of Arusha Region, about 45 kilometres (28 miles) from Laetoli, another important archaeological locality of early human occupation. The British/Kenyan paleoanthropologist-archeologist team of Mary and Louis Leakey established excavation and research programs at Olduvai Gorge that achieved great advances in human knowledge. The site is registered as one of the National Historic Sites of Tanzania.

The gorge takes its name from the Maasai word oldupai which means "the place of the wild sisal" as the East African wild sisal (Sansevieria ehrenbergii) grows abundantly throughout the gorge area. Twenty-five kilometers downstream of Lake Ndutu and Lake Masek, the gorge is the result of up to 90 m (300 ft) erosion cutting into the sediments of a Pleistocene lake bed. A side gorge, originating from Lemagrut Mountain, joins the main gorge 8 km (5.0 mi) from the mouth. This side gorge follows the shoreline of a prehistoric lake, rich in fossils and early hominin sites. Periodic flows of volcanic ash from Olmoti and Kerimasi helped to ensure preservation of the fossils in the gorge.

Ngorongoro Conservation Area (UK: /(ə)ŋˌɡɔːrəŋˈɡɔːroʊ/, US: /ɛŋˌɡɔːroʊŋˈɡɔːroʊ, əŋˌɡoʊrɔːŋˈɡoʊroʊ/) is a protected area and a UNESCO World Heritage Site located in Ngorongoro District, 180 km (110 mi) west of Arusha City in Arusha Region, within the Crater Highlands geological area of northeastern Tanzania. The area is named after Ngorongoro Crater, a large volcanic caldera within the area. The Ngorongoro Conservation Area Authority (NCAA), which administers the Ngorongoro Conservation Area (NCA), is an arm of the Tanzanian government and its boundaries follow the boundary of the Ngorongoro District in the Arusha Region. The western portion of the park abuts the Serengeti National Park (SNP). The area comprising the NCA, SNP, and Kenya's Maasai Mara game reserve is home to Great Migration, a massive annual migration of millions of wildebeest, zebras, gazelles, and other animals. The NCA also contains Olduvai Gorge, one of the most important paleoanthropological sites in the world.

Ngorongoro Conservation Area is one of the most popular attractions in Tanzania with 752,232 tourists visiting it in 2023.

Olbalbal is an administrative ward in the Ngorongoro District of the Arusha Region of Tanzania. The ward is home to the famous Olduvai Gorge. The ward covers an area of 7.893 square kilometres (3.048 sq mi) with an average elevation of 1,405 metres (4,610 ft).

In 2016, reports there were 5,387 people in the ward, from 8,969 in 2012, and 7,561 in 2002. The ward has 680 inhabitants per square kilometre (1,800/sq mi).

Laetoli is a pre-historic site located in Enduleni ward of Ngorongoro District in Arusha Region, Tanzania. The site is dated to the Plio-Pleistocene and famous for its Hominina footprints, preserved in volcanic ash. The site of the Laetoli footprints (Site G) is located 45 km south of Olduvai Gorge. The location and tracks were discovered by archaeologist Mary Leakey and her team in 1976, and were excavated by 1978. Based on analysis of the footfall impressions "The Laetoli Footprints" provided convincing evidence for the theory of bipedalism in Pliocene Hominina and received significant recognition by scientists and the public. Since 1998, paleontological expeditions have continued under the leadership of Amandus Kwekason of the National Museum of Tanzania and Terry Harrison of New York University, leading to the recovery of more than a dozen new Hominina finds, as well as a comprehensive reconstruction of the paleoecology. The site is a registered National Historic Sites of Tanzania.

Dated to 3.7 million years ago, they were the oldest known evidence of hominin bipedalism at that time. Subsequently, older Ardipithecus ramidus fossils were found with features that suggest bipedalism. With the footprints there were other discoveries excavated at Laetoli including Hominina and animal skeletal remains. Analysis of the footprints and skeletal structure showed clear evidence that bipedalism preceded enlarged brains in Hominina. At a species level, the identity of the Hominina who made the trace is difficult to construe precisely; Australopithecus afarensis is the species most commonly proposed.