The design and construction of the Treblinka extermination camp was carried out by a special SS construction team from the SS and Police Central Construction Board in Lublin led by SS-Obersturmführer Richard Thomalla. The construction work was carried out by two German companies from Legnica and Warsaw. The barbed wire fenced 17 hectares located about 500 m from the main railway road and the Małkinia – Kosów Lacki road. A telephone line was established and a convenient paved road leading from the road through the forest to the camp was built. In June 1942, a small side track was built from the already existing section of the railway line leading to the gravel pit. Materials for the construction of the camp were brought from Warsaw, Sokołów Podlaski and Kosów Lacki. The surrounding Jewish communities were forced to supply construction and installation materials. Jewish prisoners brought from the surrounding towns and prisoners of the penal labour camp were used for this purpose. Officially, the camp was called SS-Sonderkommando Treblinka, commonly referred to as Treblinka II. On 11 July 1942, construction work was completed, and SS-Untersturmführer Irmfried Eberl, a physician, became the camp commandant.

The whole camp was surrounded by a 2.5 m high double barbed wire fence, interwoven mainly with pine branches, so that you could not see what was going on behind it. In the upper part of the fence wire, juniper branches were stuffed into to raise them and mask them additionally. There were anti-tank obstacles and barbed wire coils about 40 m before the fence.

The main gate was on the north side and opened to a road named by the Germans Kurt Seidel Straße – after the oldest member of the German staff of the camp who supervised its construction. The main roads were paved, the others were lined with gravel. Behind the gate, on the right side, there was a guardhouse, and in front of it – the commandant’s office. From Kurt Seidel Straße there was a street to the east, leading to barracks for Ukrainian guards. The first large building on the east side was a dining room with a kitchen and pantry. The next two buildings, located parallel to each other, were residential barracks for guards, the so-called “wachman” (watchmen). Then there were two barracks, also located parallel to each other: the first one was a residential barrack, the second one contained rooms for a physician and a hairdresser. The barracks were named after Max Biala (Bielas). On 11 September 1942, SS-Untersturmführer Max Biala was stabbed by a Warsaw Jew Meir Berliner during the selection process on the roll call square. Berliner, and two prisoners standing next to him, was immediately killed with a spade by the guards. These barracks were inhabited by camp guards, i.e. 80-120 people.

Another object in the area of the barracks was the ZOO. There were forest animals, such as roe deer, foxes, pigeons and two peacocks. Next to the ZOO, there was a valuables sorting square. The Goldjuden unit comprising about 10-12 people registered and packed valuables, mainly money, gold, diamonds and jewellery. Their leader was SS-Unterscharführer Franz Suchomel. The Goldjuden were specialists in their sector and privileged prisoners in the camp.

Next to the commandant’s office, there was a building for the Germans, which housed a shelter, an isolation room, dentist’s and hairdresser’s offices. Behind, there was a barrack for Polish and Ukrainian women who served as cleaners and servants. Three Polish women cooked meals for the Germans.

In the prisoner part of the camp, there were barracks for prisoners called ghetto, camp 1 or lower camp. The Germans called it Wohnlager – a residential compound inhabited by 700-800 prisoners. The barracks were arranged in a horseshoe shape. All the buildings mentioned above, as well as the fuel station, the garage in which cars were kept, including the armoured car, and the coal storehouse, formed the so-called administrative and residential compound.

Another part of the camp consisted of the so-called reception area described by the Germans as Auffanglager – a transit camp. It consisted of a ramp, an undressing area for women and children where there was also a hairdresser, and the so-called cashier’s booths, i.e. a place where valuables were stored. On the opposite side there was a men’s undressing area. The undressing area was additionally fenced with barbed wire. From here, there was an arched road leading into the gas chambers called der Schlauch by the Germans, and by prisoners Himmelfahrtsstraße – the road of ascension or Himmelweg – the road to heaven. Fenced on both sides with barbed wire, it turned almost at right angles so that the influx of people into the gas chambers could be interrupted at the turn.

At the ramp, there was a large barrack where the belongings of victims were sorted. This warehouse looked similarly to a railway station from the side of the ramp and tracks. There was a large sign “Ober Majdan”. The barrack had a fake ticket window and a fake clock painted on top. The hands pointed in the direction of the alleged change of trains to Białystok and Vawkavysk and in the direction of the bath house.

An important object was the so-called “lazarett”. It was not used for treatment, but on the contrary – for killing. Above the building there was a white flag with a red cross. Behind it there was a pit in which documents, photographs, diplomas and religious objects were burned. The sick, elderly, disabled, unaccompanied children and those who could delay the pace of “work” were led to the edge of this burning pit to be quickly killed. The people brought here were seated on a bench and killed with a shot to the back of their heads. Next to the lazaret there was a pit in which the bodies of those who died during transport were buried.

The basic task was fulfilled by Totenlager – the extermination camp, referred to by the prisoners as camp 2 or upper camp. The name “upper” was derived from the terrain. It was located on a small hill, in contrast to camp 1 (lower camp) located at the bottom. The most important buildings here were the gas chambers. At the beginning of the functioning of the camp, three buildings were built, later referred to as old buildings. There is no precise information about them. Most probably they looked like in Bełżec. The barrack – 4 m wide, 8 m long and 2 m high – was built of double walls made of planks. The space between them was filled with sand to make the building airtight. The internal walls of the barrack were covered with tar paper, and the floors and walls up to a height of 1 m – with galvanised sheet metal. All doors were made of thick boards and protected from the outside with heavy wooden bars placed in iron clamps. The door, sealed with rubber, opened outwards. Next to the gas chambers there was a room with an engine, most probably dismantled from a Russian tank, and a generator that supplied the camp with electricity. The outlet of the engine’s exhaust pipe was connected to the underground pipe and opened into all three chambers. The pipes ran along the chambers, just below the ground, and their branches were directed upwards and went out at a height of 1 m from the floor to a hole in the inner wall of the chamber. These chambers were surrounded by a high fence. Death was caused by carbon monoxide poisoning, which caused paralysis of the central airways. The corpses were pulled out through manholes opened from the outside onto the ramp. They were loaded on wagons, which drove on special narrow tracks. After turning the wagon, the bodies were thrown down and the wagon was pulled for the next bodies. However, the chambers turned out to be draughty, and it took too much time for the bodies to be taken away with the wagons. As part of the reorganisation of the camp, which took place in August and September 1942, the new gas chambers were built. At Totenlager (extermination camp) there was a fenced barrack for prisoners who were used to bury and burn the bodies. There were about 300 of them. In this part of the camp, there were several deep pits for the bodies, dug mainly with the help of excavators (baggers), brought here at the end of July 1942. The trenches reached a depth of 10 m.

Initially, the murdered were buried, then burned on grates. They were built in the spring of 1943 by cremation specialist SS-Oberscharführer Herbert Floß, who came to Treblinka. To cover up the traces of the crime, a method of burning the bodies with petrol and diesel oil was introduced, and ashes mixed with sand were buried.