Task: Question Answering
Input (English): Passage: Altar 1 is found at the base of Stela 1. It is rectangular in shape with carved molding on its side.Altar 2 is of unknown provenance, having been moved to outside the administrator's house on the San Isidro Piedra Parada plantation. It is 1.59 metres (63 in) long, about 0.9 metres (35 in) wide and about 0.5 metres (20 in) high. It represents an animal variously identified as a toad and a jaguar. The body of the animal was sculptured to form a hollow 85 centimetres (33 in) across and 26 centimetres (10 in) deep. The sculpture was broken into three pieces.Altar 3 is a roughly worked flat, circular altar about 1 metre (39 in) across and 0.3 metres (12 in) high. It was probably associated originally with a stela but its original location is unknown, it was moved near to the manager's house on the San Isidro Piedra Parada plantation.Altar 5 is a damaged plain circular altar associated with Stela 2.Altar 7 is near the southern edge of the plaza on Terrace 3, where it is one of five monuments in a line running east-west.Altar 8 is a plain monument associated with Stela 5, positioned on the west side of Structure 12.Altar 9 is a low four-legged throne placed in front of Structure 11.Altar 10 was associated with Stela 13 and was found on top of the large offering of ceramics associated with that stela and the royal tomb in Structure 7A. The monument was originally a throne with cylindrical supports that was reused as an altar in the Classic period.Altar 12 is carved in the early Maya style and archaeologists consider it to be an especially early example dating to the first part of the Late Preclassic. Because of the carvings on the upper face of the altar, it is supposed that the monument was originally erected as a vertical stela in the Late Preclassic, and was reused as a horizontal altar in the Classic. At this time 16 hieroglyphs were carved around the outer rim of the altar. The carving on the upper face of the altar represents a standing human figure portrayed in profile, facing left. The figure is flanked by two vertical series of four glyphs. A smaller profile figure is depicted facing the first figure, separated from it by one of the series of glyphs. The central figure is depicted standing upon a horizontal band representing the earth, the band is flanked by two earth monsters. Above the figure is a celestial band with part of the head of a sacred bird visible in the centre. The 16 glyphs on the rim of the monument are formed by anthropomorphic figures mixed with other elements. 
Question: What altar's original location is unknown?
Output (English): Altar 3.