Problem: Background: Eratosthenes of Cyrene (; Greek: Eratosthenes o Kurenaios, IPA:
Context: Eratosthenes now continued from his knowledge about the Earth. Using his discoveries and knowledge of its size and shape, he began to sketch it. In the Library of Alexandria he had access to various travel books, which contained various items of information and representations of the world that needed to be pieced together in some organized format. In his three-volume work Geography (Greek: [Geographika] ), he described and mapped his entire known world, even dividing the Earth into five climate zones: two freezing zones around the poles, two temperate zones, and a zone encompassing the equator and the tropics. He had invented geography. He created terminology that is still used today. He placed grids of overlapping lines over the surface of the Earth. He used parallels and meridians to link together every place in the world. It was now possible to estimate one's distance from remote locations with this network over the surface of the Earth. In the Geography the names of over 400 cities and their locations were shown: this had never been achieved before. Unfortunately, his Geography has been lost to history, but fragments of the work can be pieced together from other great historians like Pliny, Polybius, Strabo, and Marcianus. The first book was something of an introduction and gave a review of his predecessors, recognizing their contributions that he compiled in the library. In this book Eratosthenes denounced Homer as not providing any insight into what he now described as geography. His disapproval of Homer's topography angered many who believed the world depicted in the Odyssey to be legitimate. He also commented on the ideas of the nature and origin of the Earth: he had thought of Earth as an immovable globe; while on its surface was a place that was changing. He had hypothesized that at one time the Mediterranean was a vast lake that covered the countries that surrounded it; and had only become connected to the ocean to the west when a passage had opened up sometime in its history. In the second book is his discovery about the circumference of the Earth. This is where, according to Pliny, "The world was grasped." Eratosthenes described his famous story of the well in Syene, described above. This book would now be considered a text on mathematical geography. His third book of the Geography contained political geography. He cited countries and used parallel lines to divide the map into sections, to give accurate descriptions of the realms. This was a breakthrough, and can be considered the beginning of geography.
Question: What was he sketching?
Answer: In his three-volume work Geography (Greek: [Geographika] ), he described and mapped his entire known world,

Problem: Background: Let's Get It On is the thirteenth studio album by American singer and songwriter Marvin Gaye. It was released on August 28, 1973, by Tamla Records. Recording sessions for the album took place during June 1970 to July 1973 at Hitsville U.S.A. and Golden World Studio in Detroit, and at Hitsville West in Los Angeles.
Context: Gaye proceeded to record some more politically conscious material at the Golden World Records studio, known as Motown's Studio B, as well as the preliminary vocals and instrumentation for some of the material to be featured on Let's Get It On. Following the earlier sessions in Detroit at Golden World, Gaye recorded at Hitsville West in Los Angeles from February to July 1973. Accompanied by an experienced group of session musicians called The Funk Brothers, who had contributed to Gaye's What's Going On, and received their first official credit, Gaye recorded the unreleased songs "The World is Rated X" and "Where Are We Going" and the single "You're the Man" (1972) at Golden World. "Where Are We Going" was later covered by trumpeter Donald Byrd. Gaye had planned the release of an album titled You're the Man, but it was later shelved for unknown reasons. The songs that were to be included on it, along with other unreleased recordings from Hitsville West and Golden World, were later featured on the 2001 re-release of Let's Get It On. The album's first recording, "Let's Get It On", was composed by Gaye with friend and former Motown label mate Ed Townsend. It was originally written by Gaye as a religious ode to life, but Motown singer-songwriter Kenneth Stover re-wrote it as a more political first draft. Upon hearing Gaye's preliminary mix of Stover's draft, Townsend protested and claimed that the song would be better suited with sexual and romantic overtones, particularly "about making sweet love." Gaye and Townsend rewrote the song's lyrics together with the original arrangements and musical accompaniment of the demo intact. The lyrics were inspired by Janis Hunter, whom Gaye had become infatuated with after meeting each other through Ed Townsend during the initial sessions. Townsend has cited Hunter's presence during the album's recording as an inspiration for Gaye. Gaye's intimate relationship with Hunter subsequently became the basis for his 1976 album I Want You. While recording the title track, he was inspired to revive unfinished recordings from his 1970 sessions at the Hitsville U.S.A. Studio. Townsend assisted Gaye with producing the rest of the album, whose recording took place at several sessions throughout 1970 to 1973. They worked on four songs together, including the ballad "If I Should Die Tonight", while Gaye composed most of the other songs, including those from past sessions. "Just to Keep You Satisfied" was originally recorded by several Motown groups, including The Originals and The Monitors, as a song dedicated to long-standing love. With re-recording the song, he had re-written the arrangement and lyrics to address the demise of his volatile marriage to Anna Gordy Gaye, who happened to be the original song's co-writer. The background vocals for the album were sung by Gaye, with the exception of "Just to Keep You Satisfied", which were done by The Originals. Most of the instrumentation for the album was done by members of The Funk Brothers, including bassist James Jamerson, guitarists Robert White and Eddie Willis, and percussionist Eddie "Bongo" Brown. Gaye also contributed on piano during the sessions.
Question: Was Let's get it on a single or an album?
Answer:
The album's first recording, "Let's Get It On",