diff --git a/common/coords.go b/common/coords.go
index 1efcf7b..6cdb714 100644
--- a/common/coords.go
+++ b/common/coords.go
@@ -21,6 +21,10 @@ type (
 		X, Y, Z int16
 	}
 
+	Cuboid struct {
+		P1, P2 Coord
+	}
+
 	KeyTransformer func(int64) int64
 	KeyEncoder     func(int64) ([]byte, error)
 	KeyDecoder     func([]byte) (int64, error)
@@ -29,6 +33,12 @@ type (
 	KeyJoiner      func(Coord) int64
 )
 
+func (cub Cuboid) Contains(c Coord) bool {
+	return c.X >= cub.P1.X && c.X <= cub.P2.X &&
+		c.Y >= cub.P1.Y && c.Y <= cub.P2.Y &&
+		c.Z >= cub.P1.Z && c.Z <= cub.P2.Z
+}
+
 func (c Coord) String() string {
 	return fmt.Sprintf("(%d, %d, %d)", c.X, c.Y, c.Z)
 }
@@ -204,3 +214,23 @@ func TranscodeInterleavedToPlain(key []byte) ([]byte, error) {
 		return EncodeStringToBytes(TransformInterleavedToPlain(pos))
 	}
 }
+
+// For correctness checks only.
+func NaiveBigMin(minz, maxz, zcode int64) int64 {
+	c1, c2 := InterleavedToCoord(minz), InterleavedToCoord(maxz)
+
+	cand := minz
+
+	for x := c1.X; x <= c2.X; x++ {
+		for y := c1.Y; y <= c2.Y; y++ {
+			for z := c1.Z; z <= c2.Z; z++ {
+				z := CoordToInterleaved(Coord{X: x, Y: y, Z: z})
+				if z > zcode && z < cand {
+					cand = z
+				}
+			}
+		}
+	}
+
+	return cand
+}
diff --git a/sqlite.go b/sqlite.go
index eb67ab8..103544b 100644
--- a/sqlite.go
+++ b/sqlite.go
@@ -23,7 +23,7 @@ const (
 	insertSql = "INSERT INTO blocks (pos, data) VALUES (?, ?)"
 	countSql  = "SELECT count(*) FROM blocks"
 	keysSql   = "SELECT pos FROM blocks"
-	rangeSql  = "SELECT pos, data FROM blocks WHERE pos BETWEEN ? AND ?"
+	rangeSql  = "SELECT pos, data FROM blocks WHERE pos BETWEEN ? AND ? ORDER BY pos"
 )
 
 type SqliteBackend struct {
@@ -283,15 +283,13 @@ func (ss *SqliteSession) AllKeys(hash []byte, done chan struct{}) (keys chan []b
 	return
 }
 
-func (ss *SqliteSession) SpatialQuery(hash, first, second []byte, done chan struct{}) (blocks chan Block, err error) {
+func (ss *SqliteSession) SpatialQuery(hash, first, second []byte, done chan struct{}) (chan Block, error) {
 
-	// No implementation for the interleaved case, yet.
 	if ss.backend.interleaved {
-		err = ErrNotImplemented
-		return
+		return ss.interleavedSpatialQuery(first, second, done)
 	}
 
-	return ss.PlainSpatialQuery(first, second, done)
+	return ss.plainSpatialQuery(first, second, done)
 }
 
 func order(a, b int64) (int64, int64) {
@@ -301,7 +299,79 @@ func order(a, b int64) (int64, int64) {
 	return b, a
 }
 
-func (ss *SqliteSession) PlainSpatialQuery(first, second []byte, done chan struct{}) (blocks chan Block, err error) {
+func (ss *SqliteSession) interleavedSpatialQuery(first, second []byte, done chan struct{}) (blocks chan Block, err error) {
+	var (
+		firstKey  int64
+		secondKey int64
+	)
+	if firstKey, err = common.DecodeStringFromBytes(first); err != nil {
+		return
+	}
+	if secondKey, err = common.DecodeStringFromBytes(second); err != nil {
+		return
+	}
+	c1 := common.PlainToCoord(firstKey)
+	c2 := common.PlainToCoord(secondKey)
+	c1, c2 = common.MinCoord(c1, c2), common.MaxCoord(c1, c2)
+
+	blocks = make(chan Block)
+
+	globalLock.RLock()
+
+	go func() {
+		defer close(blocks)
+		defer globalLock.RUnlock()
+		zmin, zmax := common.CoordToInterleaved(c1), common.CoordToInterleaved(c2)
+		// Should not be necessary.
+		zmin, zmax = order(zmin, zmax)
+		cub := common.Cuboid{P1: c1, P2: c2}
+		rangeStmt := ss.txStmt(ss.backend.rangeStmt)
+	OUTER:
+		for {
+			var (
+				err  error
+				rows *sql.Rows
+			)
+			if rows, err = rangeStmt.Query(zmin, zmax); err != nil {
+				return
+			}
+			for rows.Next() {
+				var zcode int64
+				var data []byte
+				if err = rows.Scan(&zcode, &data); err != nil {
+					log.Printf("Error in range query: %s", err)
+					break
+				}
+				c := common.InterleavedToCoord(zcode)
+				if cub.Contains(c) {
+					var encodedKey []byte
+					if encodedKey, err = common.EncodeStringToBytes(common.CoordToPlain(c)); err != nil {
+						log.Printf("Key encoding failed: %s", err)
+						break
+					}
+					select {
+					case blocks <- Block{Key: encodedKey, Data: data}:
+					case <-done:
+						rows.Close()
+						return
+					}
+				} else { // Left the cuboid
+					rows.Close()
+					zmin = common.NaiveBigMin(zmin, zmax, zcode)
+					continue OUTER
+				}
+			}
+			if err = rows.Err(); err != nil {
+				log.Printf("Error in range query: %s", err)
+			}
+			rows.Close()
+		}
+	}()
+
+	return
+}
+
+func (ss *SqliteSession) plainSpatialQuery(first, second []byte, done chan struct{}) (blocks chan Block, err error) {
 
 	var (
 		firstKey  int64
@@ -317,10 +387,10 @@ func (ss *SqliteSession) PlainSpatialQuery(first, second []byte, done chan struc
 	c2 := common.PlainToCoord(secondKey)
 	c1, c2 = common.MinCoord(c1, c2), common.MaxCoord(c1, c2)
 
-	globalLock.RLock()
-
 	blocks = make(chan Block)
 
+	globalLock.RLock()
+
 	go func() {
 		defer globalLock.RUnlock()
 		defer close(blocks)